OSD335x_EEPROM_during_boot_v04x OSD335x_EEPROM_During_Boot

OSD335x EEPROM During Boot

Rev.1 6/11/2018

!

Octavo!Systems!LLC!

Copyright!2018!

1 Introduction

When!creating!a!new!embedded!Linux!design,!getting!a!printed!circuit!board!(PCB)!to!boot!for!the!first!

time!can!have!many!unique!challenges.!!These!challenges!can!be!hardware!related:!incorrect!

connections,!improper!voltages,!bad!component!values,!etc.!or!software!related:!!incorrect!device!tree,!

improper!drivers,!bad!configuration!values!etc.!!One!common!challenge:!!how!to!properly!load!and!

configure!software!drivers!during!boot!

!

It!is!important!for!the!software!running!on!the!new!design!to!recognize!the!unique!set!of!peripherals!

and!components!used!on!the!PCB!so!that!the!drivers!can!be!properly!loaded!and!configured.!!This!can!be!

accomplished!in!many!different!ways:!!pulling!GPIO!pins,!programming!hardware!fuses,!storing!values!in!

non-volatile!memory,!etc.!!This!is!an!area!where!having!non-volatile!storage,!like!EEPROM,!either!inside!

a!System-in-Package,!as!in!the!OSD335x-SM,!or!on!the!board!can!help.!!The!Linux!images!from!

BeagleBoard.org!used!for!the!OSD335x!Family!of!devices,!identify!designs!by!a!unique!code,!a!board&ID,!

that!is!stored!within!an!EEPROM!attached!to!the!I2C0!bus.!!This!board!ID!is!then!used!within!U-Boot!to!

properly!configure!the!system.!

!

This!article!will!discuss:!!how!the!board!ID!is!used!in!U-Boot!(Section!3);!how!to!modify!U-Boot!to!ignore!

the!board!ID!(Section!4);!and!how!to!program!the!board!ID!in!an!EEPROM!either!before!boot!(Section!6)!

or!within!U-Boot!(Section!5).!!Your!preferred!method!to!program!the!board!ID,!depends!on!the!

hardware!in!your!system.!!For!example,!if!you!can!boot!from!a!microSD!card,!then!modifying!U-Boot!to!

program!the!board!ID!(either!Section!4.2!or!Section!5)!might!be!your!preferred!method.!!Similarly,!if!you!

have!an!external!I2C!programmer,!you!would!prefer!the!programming!method!outlined!in!Section!6.1.!!If!

you!would!like!to!program!the!EEPROM!over!USB!from!a!host!PC!(Section!6.2),!software!has!been!

provided!in!the!associated!zip!file!and!can!also!be!found!in!Sections!8!and!9.!

Notice:!The!information!provided!within!this!document!is!for!informational!use!only.!Octavo!Systems!

provides!no!guarantees!or!warranty!to!the!information!contained.!

2!

OSD335x EEPROM During Boot

Rev.1 6/11/2018!

!

Octavo!Systems!LLC!

Copyright!2018!

Table of Contents

1!Introduction!..........................................................................................................................................!1!

2!Revision!History!.....................................................................................................................................!3!

3!Understanding!the!Board!ID!..................................................................................................................!4!

4!Modifying!U-Boot!to!Ignore!the!Board!ID!.............................................................................................!6!

4.1!Hard-Coding!the!Board!ID!..............................................................................................................!6!

4.2!Recognizing!a!“Blank”!Board!ID!......................................................................................................!7!

5!Programming!the!Board!ID!Within!U-Boot!............................................................................................!9!

6!Programming!the!Board!ID!Outside!of!U-Boot!....................................................................................!11!

6.1!Using!an!External!I2C!Programmer!..............................................................................................!11!

6.2!Over!USB!From!a!Host!PC!.............................................................................................................!12!

6.2.1!Installing!the!Tools!................................................................................................................!12!

6.2.2!Compiling!the!Binary!.............................................................................................................!13!

6.2.3!Programming!the!Device!.......................................................................................................!14!

7!References!...........................................................................................................................................!18!

8!Appendix!A:!!hsi2cEeprom.c!................................................................................................................!19!

9!Appendix!B:!!hsi2cEeprom.lds!.............................................................................................................!26!

!

3!

OSD335x EEPROM During Boot

Rev.1 6/11/2018

!

Octavo!Systems!LLC!

Copyright!2018!

2 Revision History

Revision!Number!

Revision!Date!

Changes!

Author!

1!

6/11/2018!

Initial!Release!

Erik!Welsh!

4!

OSD335x EEPROM During Boot

Rev.1 6/11/2018!

!

Octavo!Systems!LLC!

Copyright!2018!

3 Understanding the Board ID

A!board!ID!can!be!used!for!many!different!functions:!

!

• Distinguishing!between!different!hardware!designs!

• Allowing!inventory!management!and!board!tracking,!such!as!differentiating!between!

manufacturers!

• Identifying!and!tracking!failures!for!yield!analysis!

• Compatibility!checking!for!software!

• Encoding!board!revisions!for!debug!

!

During!boot,!it!is!especially!important!to!distinguish!between!different!hardware!designs!so!that!

software!drivers!can!be!properly!configured!and!loaded.!!As!part!of!the!Linux&boot&process&for&the&

OSD335x&Family&of&devices,!U-Boot!uses!the!board!ID!to!determine!the!printed!circuit!board!(board)!on!

which!it!is!running.!!This!makes!U-Boot!more!flexible!and!allows!a!single!U-Boot!image!to!be!used!for!

many!different!development!platforms.!!You!can!see!that!there!are!many!functions!defined!in!the!U-

Boot!file!“!"#$%&'"()"%*++,-"#$%&'!./!that!are!used!to!control!what!functions!are!performed!during!the!

boot!process!(you!can!find!the!files!by!viewing!the!U-Boot!source!code,!see!reference!section!on!page!

18).!!For!example,!the!following!function!is!used!to!determine!if!the!board!is!the!Beagleboard.org®!

PocketBeagle®:!

!

This!function!uses!a!common!board!detect!infrastructure!defined!in!

“!"#$%&'"()"0$**$1"#$%&'2'3(30(!0/!and!“!"#$%&'"()"0$**$1"#$%&'2'3(30(!./!to!determine!the!

board.!!The!board!detect!infrastructure!in!turn!relies!on!a!specific!data!structure,!a!()2%*2334&$*!struct.!!

This!structure!is!found!at!the!beginning!of!an!EEPROM!on!an!I2C!bus!(I2C0!in!the!case!of!the!AM335x!

devices):!

!

static&inline&int&board_is_pb(void)&

{&

&&&&&&&&return&board_ti_is("A335PBGL");&

}&&

/**&

&*&struct&ti_am_eeprom&-&This&structure&holds&data&read&in&from&the&

&*&&&&&&&&&&&&&&&&&&&&&AM335x,&AM437x,&AM57xx&TI&EVM&EEPROMs.&

&*&@header:&This&holds&the&magic&number&

&*&@name:&The&name&of&the&board&

&*&@version:&Board&revision&

&*&@serial:&Board&serial&number&

&*&@config:&Reserved&

&*&@mac_addr:&Any&MAC&addresses&written&in&the&EEPROM&

&*&

&*&The&data&is&this&structure&is&read&from&the&EEPROM&on&the&board.&

&*&It&is&used&for&board&detection&which&is&based&on&name.&It&is&used&

&*&to&configure&specific&TI&boards.&This&allows&booting&of&multiple&

&*&TI&boards&with&a&single&MLO&and&u-boot.&

&*/&

struct&ti_am_eeprom&{&

&&&&&&&&unsigned&int&header;&

&&&&&&&&char&name[TI_EEPROM_HDR_NAME_LEN];&

&&&&&&&&char&version[TI_EEPROM_HDR_REV_LEN];&

&&&&&&&&char&serial[TI_EEPROM_HDR_SERIAL_LEN];&

&&&&&&&&char&config[TI_EEPROM_HDR_CONFIG_LEN];&

&&&&&&&&char&mac_addr[TI_EEPROM_HDR_NO_OF_MAC_ADDR][TI_EEPROM_HDR_ETH_ALEN];&

}&__attribute__&((__packed__));&

5!

OSD335x EEPROM During Boot

Rev.1 6/11/2018

!

Octavo!Systems!LLC!

Copyright!2018!

!

In!the!definition!above,!the!.3%'3&!field!is!a!“magic!number”,!i.e.!a!constant,!

5627789:;2<7=>792;=?6@A!with!a!value!of!B-77++,,==.!!This!structure!can!be!generically!referred!to!

as!a!“board!ID”!even!though!it!has!many!different!pieces!of!information.!!If!you!read!the!contents!of!an!

EEPROM!from!the!Octavo!Systems!development!board!OSD3358-SM-RED,!you!can!see!that!it!follows!the!

above!data!structure!format:!

!

Unfortunately,!the!reliance!on!the!board!ID!during!U-Boot!can!cause!problems!when!first!booting!a!

board!after!manufacturing.!!By!default,!all!EEPROMs!are!initially!unprogrammed!(i.e.!all!bytes!have!a!

value!of!0xFF)!when!placed!on!a!board.!!Therefore,!when!U-Boot!first!comes!up!and!reads!the!

unprogrammed!board!ID,!it!will!read!a!value!that!does!not!match!any!board!causing!the!software!to!

hang!because!U-Boot!is!unable!to!know!how!to!configure!any!peripheral!to!continue!the!boot.!!

Unfortunately,!the!software!hang!occurs!before!the!U-Boot!console!is!active!which!can!be!mistaken!for!

hardware!bring-up!problems!(i.e.!power!is!applied!to!the!board,!but!nothing!happens).!

!

To!mitigate!this!issue,!you!can!either!modify!U-Boot!to!ignore!the!board!ID!information!within!the!

EEPROM!(i.e.!hard!code!the!board!ID),!or!you!can!program!the!EEPROM!to!have!the!correct!board!ID!

information!for!the!given!system.!

!

Address&&&&Value&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&ASCII&Value&

00000000&&&AA&55&33&EE&&41&33&33&35&&42&4E&4C&54&&4F&53&30&30&&.U3.A335BNLTOS00&

00000010&&&00&00&00&00&&00&00&00&00&&00&00&00&00&&FF&FF&FF&FF&&................&

6!

OSD335x EEPROM During Boot

Rev.1 6/11/2018!

!

Octavo!Systems!LLC!

Copyright!2018!

4 Modifying U-Boot to Ignore the Board ID

One!way!to!overcome!an!unprogrammed!EEPROM!is!to!modify!U-Boot!itself!so!that!either!the!board!ID!

is!ignored!by!U-Boot!or!that!the!value!of!an!unprogrammed!EEPROM!is!recognized!as!a!“blank”!board.!!

While!modifying!U-Boot!can!be!a!good!short-term!solution!to!work!around!this!condition,!it!is!not!

necessarily!a!good!long-term!solution!to!have!U-Boot!either!ignore!the!board!ID!or!for!the!board!to!be!

recognized!as!“blank”.!!Doing!this!in!a!production!software!image!can!be!problematic!in!the!case!that!

revisions!of!the!system!have!components!that!must!be!handled!differently!during!boot.!!It!also!limits!the!

reusability!of!the!production!software!image!across!multiple!products.!!Therefore,!it!is!recommended!to!

only!ignore!the!board!ID!during!the!prototyping!phase!of!a!design!and!to!program!the!EEPROM!with!a!

valid!board!ID!during!production!(See!Section!5).!

!

To!modify!U-Boot,!you!first!must!be!familiar!with!the!process!needed!to!build!U-Boot.!!You!can!find!

instructions!on!how!to!do!this!at!https://eewiki.net/display/linuxonarm/BeagleBone+Black!!Once!you!

are!familiar!with!the!process,!there!are!two!methods!you!can!follow!to!update!U-Boot!to!bypass!the!

board!ID!checks.!

!

4.1 Hard-Coding the Board ID

In!this!first!method,!you!can!manually!modify!U-Boot!to!hard!code!a!function!within!

“!"#$%&'"()"%*++,-"#$%&'!./!so!that!the!board!has!a!fixed!identity!(i.e.!the!board!ID!is!“hard!coded”).!!

For!example,!to!make!U-Boot!always!identify!the!board!as!“BeagleBone®!Black”,!you!will!need!to!make!

the!following!modification:!

!

By!returning!“1”!(i.e.!true),!this!function!will!make!U-Boot!believe!that!the!board!is!BeagleBone®!Black!

and!follow!the!boot!process!for!BeagleBone®!Black.!!If!this!works!for!your!system!(i.e.!you!have!similar!

components!to!the!BeagleBone®!Black!for!booting,!like!an!eMMC!on!MMC1!and!an!SD!card!on!MMC0),!

then!you!can!use!this!to!bypass!the!board!ID!check.!

!

static&inline&int&board_is_bone_lt(void)&

{&

//&&&&&&return&board_ti_is("A335BNLT");&&--&Hard&code&board&ID&to&BeagleBone&Black&

&&&&&&&&return&1;&

}&

7!

OSD335x EEPROM During Boot

Rev.1 6/11/2018

!

Octavo!Systems!LLC!

Copyright!2018!

4.2 Recognizing a “Blank” Board ID

Another!method!to!ignore!the!board!ID,!is!to!update!U-Boot!to!recognize!the!unprogrammed!EEPROM!

value!as!“blank”.!!To!do!this,!a!patch!has!been!created!that!can!help!with!this!process.!!As!part!of!the!U-

Boot!build!process!there!are!two!patches!that!must!be!downloaded!and!applied!to!the!U-Boot!code!

base:!

!

In!addition!to!these!patches,!another!patch!can!be!downloaded!that!will!configure!U-Boot!to!recognize!

the!unprogrammed!EEPROM!value!as!a!“blank”!board!and!potentially!program!the!EEPROM!with!a!

board!ID.!!You!can!find!this!patch!at:!

!

https://github.com/RobertCNelson/Bootloader-Builder/blob/master/patches/v2018.03-rc1/0002-

NFM-Production-eeprom-assume-device-is-BeagleBone-Bl.patch!!

!

If!you!look!at!the!patch,!you!can!see!how!the!files!in!U-Boot!will!be!modified!to!ignore!the!board!ID!by!

recognizing!the!unprogrammed!EEPROM!as!a!“blank”!(i.e.!“A335BLNK”)!board!and!then!potentially!

program!a!board!ID!value!into!the!EEPROM.!!If!you!look!at!lines!153!to!167!of!the!patch:!!

!

You!can!see!that!if!the!board!is!“blank”!(i.e.!“A335BLNK”),!then!the!boot!process!will!check!to!see!if!the!

file!“"#$$("!334&$*!(-(/!exists!in!the!root!file!system!of!the!boot!image.!!If!it!does,!then!it!will!

automatically!run!the!334&$*24&$C&%*!command,!defined!in!BBBDE%*++,-23F*EG71F!(-(E#$$(HE1E

I)-3J!4%(0.,!utilizing!the!variables!set!in!the!“"#$$("!334&$*!(-(/!file.!!If!you!look!at!the!334&$*24&$C&%*!

command!(lines!1607!to!1617!of!BBBDE%*++,-23F*EG71F!(-(E#$$(HE1EI)-3J!4%(0.):!

!

wget&-c&https://rcn-ee.com/repos/git/u-boot-patches/v2018.03/0001-am335x_evm-uEnv.txt-bootz-n-fixes.patch&

wget&-c&https://rcn-ee.com/repos/git/u-boot-patches/v2018.03/0002-U-Boot-BeagleBone-Cape-Manager.patch&

Caveat:!

!

The!version!of!U-Boot!and!the!patches!listed!above!may!not!have!be!the!same!in!the!future.!!The!

correct!versions!and!names!should!be!listed!in!the!instructions!to!build!U-Boot.!

@@&-190,6&+190,14&@@&

&&&&&"setenv&fdtfile&am335x-boneblack.dtb;&"&\&

&& & & "fi;&"&\&

&& & "fi;&"&\&

+& & "if&test&$board_name&=&A335BLNK;&then&"&\&

+& & & "if&test&-e&mmc&0:1&/boot/.eeprom.txt;&then&"&\&

+&&&&"load&mmc&0:1&${loadaddr}&/boot/.eeprom.txt;"&\&

+&&&&"env&import&-t&${loadaddr}&${filesize};"&\&

+&&&&"echo&Loaded&environment&from&/boot/.eeprom.txt;"&\&

+&&&&"run&eeprom_program;&"&\&

+& & & "fi;"&\&

+& & & "setenv&fdtfile&am335x-boneblack-emmc-overlay.dtb;&fi;&"&\&

&& & "if&test&$board_name&=&BBBW;&then&"&\&

&& & & "setenv&fdtfile&am335x-boneblack-wireless.dtb;&fi;&"&\&

&& & "if&test&$board_name&=&BBG1;&then&"&\&

8!

OSD335x EEPROM During Boot

Rev.1 6/11/2018!

!

Octavo!Systems!LLC!

Copyright!2018!

!

You!can!see!that!depending!on!the!value!of!the!variable!#$%&'2334&$*2.3%'3&,!the!appropriate!board!

ID!value!will!be!programmed!into!the!EEPROM.!!As!of!this!writing,!the!acceptable!values!for!

#$%&'2334&$*2.3%'3&!are:!

!

• board_eeprom_header=bbb_blank&

• board_eeprom_header=bbbl_blank&

• board_eeprom_header=bbbw_blank&

• board_eeprom_header=os00_blank&

• board_eeprom_header=beaglelogic_blank&

&

If!you!need!to!add!in!a!custom!board!ID!value!to!be!programmed!into!the!EEPROM,!it!is!straight!forward!

to!extend!the!code!from!the!patches!(i.e.!the!334&$*24&$C&%*!command!and!the!

7789:;289:?9=;;6K?!#define).!!In!this!way,!you!can!use!the!updated!U-Boot!image!to!program!all!

of!your!systems!so!that!they!can!have!a!valid!board!ID.!

!

+& "eeprom_program="\&

+& & "if&test&$board_eeprom_header&=&bbb_blank;&then&"&\&

+& & & "run&eeprom_dump;&run&eeprom_blank;&run&eeprom_bbb_header;&run&eeprom_dump;&

reset;&fi;&"&\&

+& & "if&test&$board_eeprom_header&=&bbbl_blank;&then&"&\&

+& & & "run&eeprom_dump;&run&eeprom_blank;&run&eeprom_bbb_header;&run&

eeprom_bbbl_footer;&run&eeprom_dump;&reset;&fi;&"&\&

+& & "if&test&$board_eeprom_header&=&bbbw_blank;&then&"&\&

+& & & "run&eeprom_dump;&run&eeprom_blank;&run&eeprom_bbb_header;&run&

eeprom_bbbw_footer;&run&eeprom_dump;&reset;&fi;&"&\&

+& & "if&test&$board_eeprom_header&=&os00_blank;&then&"&\&

+& & & "run&eeprom_dump;&run&eeprom_blank;&run&eeprom_bbb_header;&run&

eeprom_os00_footer;&run&eeprom_dump;&reset;&fi;&"&\&

+& & "if&test&$board_eeprom_header&=&beaglelogic_blank;&then&"&\&

+& & & "run&eeprom_dump;&run&eeprom_blank;&run&eeprom_beaglelogic;&run&eeprom_dump;&

reset;&fi;&&\0"&\&

9!

OSD335x EEPROM During Boot

Rev.1 6/11/2018

!

Octavo!Systems!LLC!

Copyright!2018!

5 Programming the Board ID Within U-Boot

If!you!used!the!“hard-coding!method”!or!did!not!use!the!automated!EEPROM!programming!functions!of!

the!“blank!method”!in!Section!4,!you!can!still!program!the!board!ID!manually!in!U-Boot.!!Once!you!have!

been!able!to!boot!to!the!U-Boot!console!(i.e.!you!have!bypassed!the!board!ID!check),!it!is!straight!

forward!to!program!values!in!the!EEPROM!corresponding!to!the!board!ID!structure.!!From!the!U-Boot!

prompt,!you!only!need!to!use!the!)L0!command!to!program!the!EEPROM!with!the!appropriate!value.!!

The!commands!below!can!be!used!to!program!the!board!ID!for!the!OSD3358-SM-RED!board.!

!

Each!of!the!values!passed!to!the!I2C!write!command!(e.g.!42!or!4e)!is!a!hexadecimal!ASCII!value!

(https://www.asciitable.com/).!!Once!the!1%*3!and!F3&J)$1!fields!of!the!EEPROM!data!structure!are!

written,!you!can!check!that!the!programming!was!successful!using!an!I2C!read!command:!

!

//&Set&i2c&device&

i2c&dev&0&

&

//&Set&the&EEPROM&header&“magic&number”:&&0xAA5533EE&

i2c&mw&0x50&0x00.2&aa&

i2c&mw&0x50&0x01.2&55&

i2c&mw&0x50&0x02.2&33&

i2c&mw&0x50&0x03.2&ee&

&

//&Set&the&EEPROM&name&(bytes&0&–&4):&&“A335”&

i2c&mw&0x50&0x04.2&41&

i2c&mw&0x50&0x05.2&33&

i2c&mw&0x50&0x06.2&33&

i2c&mw&0x50&0x07.2&35&

&

//&Set&the&EEPROM&name&(bytes&4&–&7):&&“BNLT”&

i2c&mw&0x50&0x08.2&42&

i2c&mw&0x50&0x09.2&4e&

i2c&mw&0x50&0x0a.2&4c&

i2c&mw&0x50&0x0b.2&54&

&

//&Set&the&EEPROM&version:&&“OS00”&–&OSD3358-SM-RED&development&platform&

i2c&mw&0x50&0x0c.2&4f&

i2c&mw&0x50&0x0d.2&53&

i2c&mw&0x50&0x0e.2&30&

i2c&mw&0x50&0x0f.2&30&

=>&i2c&dev&0&

Setting&bus&to&0&

&

=>&i2c&md&0x50&0x00.2&20&

0000:&aa&55&33&ee&41&33&33&35&42&4e&4c&54&4f&53&30&30&&&&.U3.A335BNLTOS00&

0010:&00&00&00&00&00&00&00&00&00&00&00&00&ff&ff&ff&ff&&&&................&

Caveat:!

!

The!version!field!of!early!revisions!of!the!OSD3358-SM-RED!had!a!value!of!“BBNR”!(i.e.!42!42!4e!52)!

10!

OSD335x EEPROM During Boot

Rev.1 6/11/2018!

!

Octavo!Systems!LLC!

Copyright!2018!

At!this!point,!the!board!has!been!successfully!programmed!so!that!it!can!now!boot!a!default!Linux!image!

from!BeagleBoard.org®.!!However,!if!you!would!also!like!to!add!a!serial!number!to!the!EEPROM,!you!

may!do!so!in!the!next!twelve!(12)!bytes!(above!example!has!a!serial!number!of:!000000000000).!

!

11!

OSD335x EEPROM During Boot

Rev.1 6/11/2018

!

Octavo!Systems!LLC!

Copyright!2018!

6 Programming the Board ID Outside of U-Boot

If!there!is!no!removable!media,!like!an!microSD!card,!in!a!system,!it!can!be!difficult!to!modify!and!load!

U-Boot!to!program!an!EEPROM.!!However,!it!is!possible!to!program!the!board!ID!directly!without!

modifying!U-Boot!by!either!using!an!external!I2C!programmer!or!over!USB!from!a!host!PC.!

!

6.1 Using an External I2C Programmer

To!program!the!board!ID!using!an!external!I2C!programmer,!there!are!two!requirements:!

!

1. The!I2C0!pins!must!be!accessible!(i.e.!the!pins!must!be!brought!out!to!a!header!or!test!points)!so!

that!they!can!be!connected!to!an!external!I2C!programmer!

2. The!AM335x!within!the!OSD335x!family!of!devices!should!be!held!in!reset!(i.e.!WARMRSTN!

should!be!held!low).!

!

Making!the!I2C0!pins!accessible!is!straight!forward!but!must!be!added!during!the!hardware!design!phase!

of!your!system.!!If!the!I2C0!pins!are!not!accessible,!it!will!make!using!an!external!I2C!programmer!

difficult!to!impossible.!

!

Also,!the!AM335x!within!the!OSD335x!family!of!devices!should!be!held!in!reset!when!using!an!external!

I2C!programmer.!!This!will!guarantee!that!there!is!only!one!master!on!the!I2C0!bus!and!that!there!will!be!

no!conflicts!with!the!AM335x!trying!to!control!the!bus.!!This!requires!that!a!reset!button!or!header!exists!

that!can!hold!the!WARMRSTN!pin!low.!

!

12!

OSD335x EEPROM During Boot

Rev.1 6/11/2018!

!

Octavo!Systems!LLC!

Copyright!2018!

6.2 Over USB From a Host PC

To!program!the!board!ID!over!USB!from!host!PC,!you!can!use!a!custom!bare-metal!program!that!will!

write!values!to!the!EEPROM.!!This!method!requires:!

!

• AM335x!StarterWare!02.00.01.01!

• GCC!cross!compiler!

• CCS!UniFlash!v3.4.1!

• Target!system!to!boot!from!USB!

• Optional:!!UART-to-USB!adapter!and!Terminal!Emulator!(such!as!Putty2)!

!

For!the!target!system!to!boot!from!USB,!the!boot!mode!must!try!to!use!the!USB!peripheral!to!download!

a!boot!image.!!For!example,!if!the!SYSBOOT[4:0]!pins!have!a!value!of!11000b,!i.e.!the!boot!mode!

selected!by!the!SD!Boot!button!on!the!OSD3358-SM-RED,!then!the!processor!will!try!SPI0,!MMC0,!USB0,!

and!UART0,!in!that!order,!to!boot.!!This!will!allow!programming!over!USB0.!

!

6.2.1 Installing the Tools

To!install!StarterWare!and!the!GCC!cross!compiler,!please!follow!the!instructions!from!Sections!3!

(61J(%MM)1CNO(%&(3&P%&3NI$&N=;++,-)!and!4!(61J(%MM)1CNQ)1%&$N?@@N@$*4)M3&)!of!the!Bare&Metal&

Applications&on&OSD335x&using&U-Boot!application!note!which!can!be!found!here.!!The!instructions!

provided!below!assume!that!both!of!these!tools!were!installed!on!a!Linux!system!(Ubuntu!16.04!was!

used!in!the!example).!!However,!the!instructions!should!be!similar!for!a!Windows!system!as!long!as!the!

GCC!compiler!is!used.!

!

To!install!the!CCS!UniFlash!first!follow!the!61J(%MM%()$1N61J(&G0()$1J!from:!

!http://processors.wiki.ti.com/index.php/CCS_UniFlash_v3.4.1_Release_Notes!

!

The!instructions!provided!below!assume!that!this!tool!was!installed!on!a!Windows!system!(Window!10!

was!used!in!the!example).!!However,!the!instructions!should!be!similar!for!a!Linux!system.!

!

Once!the!UniFlash!tool!is!installed,!you!will!need!to!modify!the!configuration!files!so!that!the!tool!uses!

more!appropriate!IP!addresses.!!By!default,!the!configuration!files!use!the!192.168.100!subnet.!!

However,!the!USB!RNDIS!connection!on!the!example!system!was!configured!to!use!the!192.168.0!

subnet.!!Therefore,!the!following!configuration!files!need!to!be!modified:!

!

File!uniflash_3.4/third_party/sitara/opendhcp.ini:!

!

• Line!22:!

o Original!version:!

§ 192.168.100.1

o New!version:!

§ 192.168.0.1

• Lines!117!–!119:!

o Original!version:!

§ DHCPRange=192.168.100.2-192.168.100.254

§ NextServer=192.168.100.1

§ Router=192.168.100.1

13!

OSD335x EEPROM During Boot

Rev.1 6/11/2018

!

Octavo!Systems!LLC!

Copyright!2018!

o New!version:!

§ DHCPRange=192.168.0.2-192.168.0.254

§ NextServer=192.168.0.1

§ Router=192.168.0.1

!

File!uniflash_3.4/third_party/sitara/opentftp.ini:!

!

• Line!23:!

o Original!version!

§ 192.168.100.1

o New!version!

§ 192.168.0.1

!

Depending!on!your!USB!RNDIS!connection!configuration,!you!should!adjust!the!default!subnet!

accordingly.!!If!you!do!not!wish!to!modify!the!configuration!files,!you!can!always!manually!modify!the!

subnet!values!when!running!the!tool.!

!

6.2.2 Compiling the Binary

Next,!you!will!need!to!modify!the!hsi2c_eeprom!example!in!order!to!create!a!program!that!will!program!

a!custom!value!into!the!EEPROM!to!set!the!board!ID.!!As!part!of!the!installation!instruction!for!the!GCC!

cross!compiler,!you!should!have!set!the!LIB_PATH!environment!variable.!!This!variable!must!be!set!for!

the!makefiles!for!the!GCC!build!to!work!correctly.!!!

!

1. Replace!the!.J)L0734&$*!0!file!with!the!one!provided!(see!Appendix!A:!!hsi2cEeprom.c)!

a. Change!directories!to:!

=;++,R2O(%&(3&P%&32BL2BB2BD2BD"3-%*4M3J"#3%CM3#$13".J)L02334&$*!

b. Replace!the!contents!of!.J)L0734&$*!0!with!the!provided!code.!!This!code!uses!a!polling!

I2C!method!to!read!values!from!and!write!values!to!the!EEPROM.!

!

2. Modify!the!.J)L0734&$*!0!file!with!your!appropriate!board!ID!value!

a. On!approximately!line!85,!there!are!two!S'3I)13!variables!that!tell!the!program!the!

number!of!bytes!to!write!the!EEPROM!(NUM_BYTES_TO_WRITE)!as!well!as!the!values!to!

write!to!the!EEPROM!(EEPROM_VALUE_TO_WRITE).!

b. Currently,!these!values!are!set!to!the!OSD3358-SM-RED!board!ID.!!These!values!should!

be!updated!to!program!your!board!ID.!

!

3. Replace!the!.J)L02334&$*!linker!command!file!with!the!one!provided(See!Appendix!B:!!

hsi2cEeprom.lds):!

a. Change!directories!to:!

=;++,R2O(%&(3&P%&32BL2BB2BD2BD"#G)M'"%&*FT%"C00"%*++,-"#3%CM3#$13".J)L02334

&$*!

b. Replace!the!contents!of!the!linker!command!file,!.J)L0734&$*!M'J,!with!the!provided!

code.!!This!will!place!the!program!within!the!internal!AM335x!memory!so!that!it!can!be!

used!directly!as!a!Secondary!Program!Loader!(SPL)!without!having!to!initialize!DDR.!

!

14!

OSD335x EEPROM During Boot

Rev.1 6/11/2018!

!

Octavo!Systems!LLC!

Copyright!2018!

4. Build!the!program!

a. In!the!same!directory!as!the!linker!command!file:!

=;++,R2O(%&(3&P%&32BL2BB2BD2BD"#G)M'"%&*FT%"C00"%*++,-"#3%CM3#$13".J)L02334

&$*!

b. Execute!the!following!commands:!

i. make clean

ii. make

!

5. Collect!the!compiled!binary!to!program!into!the!device!

a. Change!directories!to:!!

=;++,R2O(%&(3&P%&32BL2BB2BD2BD"#)1%&U"%&*FT%"C00"%*++,-"#3%CM3#$13".J)L0233

4&$*">3#GC!

b. Collect!the!following!file!to!be!used!to!program!the!device:!!.J)L0734&$*!#)1!

!

If!you!need!to!change!the!value!programmed!into!the!EEPROM!for!the!board!ID,!you!can!update!the!

.J)L0734&$*!0!file!from!Step!2!and!then!recompile!the!executable!using!Step!4.!

!

6.2.3 Programming the Device

Now!that!you!have!the!executable!program,!.J)L0734&$*!#)1,!that!will!program!the!board!ID!into!the!

EEPROM,!you!need!to!use!the!UniFlash!tool!to!load!and!run!the!program.!

!

1. Update!the!UniFlash!file!to!load!into!the!device!

a. Open!folder:!!@VW=;++,-2XM%J.($$MW)*%C3J!

b. Copy!.J)L0734&$*!#)1!to!this!directory!

c. Change!the!name!of!the!file!to!GE#$$(EJ4ME&3J($&3!#)1!

!

! !

15!

OSD335x EEPROM During Boot

Rev.1 6/11/2018

!

Octavo!Systems!LLC!

Copyright!2018!

2. Setup!the!UniFlash!tool!

a. Open!the!UniFlash!tool!

b. Select!“New!Target!Configuration”!

c. Select!“Sitara!Flash!Connections”!for!“Conection”!

d. Select!“Sitara!Flash!Devices”!for!“Board!or!Device”!

!

e. At!this!point,!you!should!see!the!following!settings!in!the!tool!(These!can!be!adjusted!if!

they!are!not!correct!for!your!setup).!

!

16!

OSD335x EEPROM During Boot

Rev.1 6/11/2018!

!

Octavo!Systems!LLC!

Copyright!2018!

3. Optional:!!View!program!output!

a. Connection!UART-to-USB!adapter!to!the!UART0!interface!of!the!target!system!

b. Start!a!terminal!emulator!program!(such!as!Putty)!

!

This!will!allow!you!to!see!the!output!of!the!program!on!UART0!but!is!optional.!

!

4. Load!and!execute!the!program!

a. Connect!a!USB!cable!from!the!appropriate!USB!interface!of!the!target!system!to!the!

host!system!that!is!running!CCS!UniFlash.!

b. Boot!the!board!in!the!appropriate!boot!mode!

i. Note:!!In!Windows,!you!should!hear!a!notification!that!the!target!system!has!

connected!to!the!host!using!USB!RNDIS.!!You!should!also!be!able!to!see!this!

connection!in!the!“Network!Connections”!window.!!By!looking!at!this!

connection,!you!can!debug!any!IP!address!issues!you!may!have!with!the!

UniFlash!IP!settings.!

c. Click!the!“Start!Flashing”!button!in!UniFlash!

!

d. After!a!few!seconds!(up!to!a!minute),!you!should!see!the!target!system!populate!a!line!

in!the!“Status!View”.!!This!will!always!show!a!“Progress!%”!of!“0%”!even!though!the!

program!has!been!loaded!and!executed!by!the!target!system.!!You!can!view!the!

download!of!the!executable!with!a!tool!such!as!WireShark3.!

! !

17!

OSD335x EEPROM During Boot

Rev.1 6/11/2018

!

Octavo!Systems!LLC!

Copyright!2018!

e. If!you!have!the!optional!program!output!enabled,!then!you!should!see!the!following!

output!on!the!UART0!interface!(with!the!value!that!you!set!in!the!program!instead!of!

the!default!value!pictured!below).!

!

f. Close!UniFlash!since!the!target!system!has!been!successfully!programmed.!

!

Caveat:!

!

Please!ensure!that!the!EEPROM!is!not!write!protected!when!you!try!to!write!the!board!ID!value!into!

the!EEPROM.!!For!the!OSD335x-SM,!this!means!pulling!the!7789:;2P8!pin!low.!

18!

OSD335x EEPROM During Boot

Rev.1 6/11/2018!

!

Octavo!Systems!LLC!

Copyright!2018!

7 References

!

For!more!information!on!software!and!optional!tools,!please!refer!to!the!following!links:!

!

1. U-Boot! ! https://github.com/u-boot/u-boot!!

2. Putty!! ! https://www.putty.org/!!

3. WireShark!! https://www.wireshark.org/!

! !

19!

OSD335x EEPROM During Boot

Rev.1 6/11/2018

!

Octavo!Systems!LLC!

Copyright!2018!

8 Appendix A: hsi2cEeprom.c

/**

* \file eeprom_writer.c

*

* \brief Application to write a blank EEPROM with a value. This will allow

* customers to set the Board ID to configure U-Boot.

*

* Application Configuration:

*

* Modules Used:

* I2C0

* UART0

*

* Configurable parameters:

* NUM_BYTES_TO_WRITE

* EEPROM_VALUE_TO_WRITE

*

* Hard-coded configuration of other parameters:

* Bus frequency - 100kHz

* Addressing mode - 7bit

* I2C Instance - 0

* Slave Address - 0x50

* EEPROM memory address - 0x0000

*

* Limitations:

* With no flashed data in EEPROM, if the application tries to read from

* EEPROM, then the data values read would be "0xFF", which indicates an

* invalid EEPROM data.

*/

/*

*/

/*

*/

/*

* Redistribution and use in source and binary forms, with or without

* modification, are permitted provided that the following conditions

* are met:

*

* Redistributions of source code must retain the above copyright

* notice, this list of conditions and the following disclaimer.

*

* Redistributions in binary form must reproduce the above copyright

* notice, this list of conditions and the following disclaimer in the

* documentation and/or other materials provided with the

* distribution.

*

* Neither the name of Texas Instruments Incorporated nor the names of

* its contributors may be used to endorse or promote products derived

* from this software without specific prior written permission.

*

* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

*

*/

20!

OSD335x EEPROM During Boot

Rev.1 6/11/2018!

!

Octavo!Systems!LLC!

Copyright!2018!

#include "hw_types.h"

#include "hw_control_AM335x.h"

#include "hw_cm_wkup.h"

#include "watchdog.h"

#include "evmAM335x.h"

#include "hsi2c.h"

#include "uartStdio.h"

#include "soc_AM335x.h"

#include "stdio.h"

/******************************************************************************

** INTERNAL MACRO DEFINITIONS

*******************************************************************************/

//

// MODIFY THIS CODE

// - NUM_BYTES_TO_WRITE should match the number of data values provided in

EEPROM_VALUE_TO_WRITE

// - NUM_BYTES_TO_WRITE should not exceed BUFFER_SIZE

//

#define NUM_BYTES_TO_WRITE (16)

#define EEPROM_VALUE_TO_WRITE {0xAA, 0x55, 0x33, 0xEE, 0x41, 0x33, 0x33, 0x35, 0x42,

0x4E, 0x4C, 0x54, 0x4F, 0x53, 0x30, 0x30}

//

// END MODIFY THIS CODE

//

/* I2C address of AT24C256 eeprom */

#define I2C_SLAVE_ADDR (0x50)

/* Higher byte address (i.e A8-A15) */

#define E2PROM_ADDR_MSB (0x00)

/* Lower byte address (i.e A0-A7) */

#define E2PROM_ADDR_LSB (0x00)

/* I2C instance */

#define I2C_0 (0x0u)

/* System clock fed to I2C module - 48Mhz */

#define I2C_SYSTEM_CLOCK (48000000u)

/* Internal clock used by I2C module - 12Mhz */

#define I2C_INTERNAL_CLOCK (12000000u)

/* I2C bus speed or frequency - 100Khz */

#define I2C_OUTPUT_CLOCK (100000u)

/* I2C interrupt flags to clear */

#define I2C_INTERRUPT_FLAG_TO_CLR (0x7FF)

/* Buffer Size */

#define BUFFER_SIZE (1024)

/******************************************************************************

** INTERNAL FUNCTION PROTOTYPES

*******************************************************************************/

static void setup_platform(void);

static void print_data(unsigned char *data, unsigned int size);

static void setup_I2C(void);

static void setup_UART(void);

static void SetupI2CTransmit(unsigned int dcount);

static void SetupReception(unsigned int dcount);

21!

OSD335x EEPROM During Boot

Rev.1 6/11/2018

!

Octavo!Systems!LLC!

Copyright!2018!

/******************************************************************************

** INTERNAL VARIABLE DEFINITIONS

*******************************************************************************/

volatile unsigned char dataToSlave[BUFFER_SIZE];

volatile unsigned char dataFromSlave[BUFFER_SIZE];

volatile unsigned int tCount;

volatile unsigned int rCount;

/******************************************************************************

** FUNCTION DEFINITIONS

******************************************************************************/

int main(void)

{

volatile unsigned char data[NUM_BYTES_TO_WRITE] = EEPROM_VALUE_TO_WRITE;

volatile unsigned int i, j;

// Setup the platform

setup_platform();

// Initialize variables

for (i = 0; i < (NUM_BYTES_TO_WRITE + 2); i++) {

dataToSlave[i] = 0;

dataFromSlave[i] = 0;

}

UARTPuts("Octavo Systems EEPROM Writer v0.1\n", -1);

// Write data to the EEPROM

// - Setup Address

// - Copy data to write

// - Transmit data

//

UARTPuts("Writing value to EEPROM\n", -1);

tCount = 0;

dataToSlave[0] = E2PROM_ADDR_MSB;

dataToSlave[1] = E2PROM_ADDR_LSB;

for (i = 0; i < NUM_BYTES_TO_WRITE; i++) {dataToSlave[i + 2] = data[i];}

print_data((unsigned char *)&dataToSlave[2], NUM_BYTES_TO_WRITE);

SetupI2CTransmit(NUM_BYTES_TO_WRITE + 2);

UARTPuts("Done writing.\n", -1);

// Wait for EEPROM to finish writing

j = 0;

for (i = 0; i < 1000000; i++) {

j++;

}

// Read data back from EEPROM

// - Use the address from the current dataToSlave buffer

rCount = 0;

tCount = 0;

SetupReception(NUM_BYTES_TO_WRITE);

// Print data from EEPROM

UARTPuts("Value Written:\n", -1);

print_data((unsigned char *)dataFromSlave, NUM_BYTES_TO_WRITE);

UARTPuts("Done.\n", -1);

while(1);

}

22!

OSD335x EEPROM During Boot

Rev.1 6/11/2018!

!

Octavo!Systems!LLC!

/*

* \brief This function Initializes WDT, UART, and I2C

*

* \param none

*

* \return none

*/

void setup_platform(void)

{

// Disable WDT

HWREG(SOC_WDT_1_REGS + WDT_WSPR) = 0xAAAAu;

while(HWREG(SOC_WDT_1_REGS + WDT_WWPS) != 0x00);

HWREG(SOC_WDT_1_REGS + WDT_WSPR) = 0x5555u;

while(HWREG(SOC_WDT_1_REGS + WDT_WWPS) != 0x00);

/* Enable the control module */

HWREG(SOC_CM_WKUP_REGS + CM_WKUP_CONTROL_CLKCTRL) =

CM_WKUP_CONTROL_CLKCTRL_MODULEMODE_ENABLE;

/* UART Initialization */

setup_UART();

UARTStdioInit();

/* I2C Initialization */

setup_I2C();

}

/*

** Print data

*/

static void print_data(unsigned char *data, unsigned int size) {

unsigned char ch[2];

unsigned char temp;

unsigned int i;

if ((BUFFER_SIZE / 4) < size) {

// Print error message

UARTPuts("Too much data requested \n", -1);

return;

}

ch[1] = 0;

// Print first character

UARTPuts("[", 1);

for (i = 0; i < size; i++) {

// Collect the Most Significant Nibble of the data byte

temp = ((data[i] & 0xF0) >> 4);

if (temp < 10) {

// UARTPrintf("%c", (temp + 0x30));

ch[0] = temp + 0x30;

UARTPuts(ch, 1);

} else {

// UARTPrintf("%c", (temp + 0x37));

ch[0] = temp + 0x37;

UARTPuts(ch, 1);

}

// Collect the Least Significant Nibble of the data byte

temp = (data[i] & 0x0F);

if (temp < 10) {

// UARTPrintf("%c", (temp + 0x30));

ch[0] = temp + 0x30;

23!

OSD335x EEPROM During Boot

Rev.1 6/11/2018

!

Octavo!Systems!LLC!

UARTPuts(ch, 1);

} else {

// UARTPrintf("%c", (temp + 0x37));

ch[0] = temp + 0x37;

UARTPuts(ch, 1);

}

if (i < (size - 1)) {

UARTPuts(", ", 2);

}

// Print final character

UARTPuts("]\n", -1);

}

/******************************************************************************

** I2C FUNCTION DEFINITIONS

******************************************************************************/

/*

* \brief Configure I2C0 on which the PMIC is interfaced

*

* \param none

*

* \return none

*/

void setup_I2C(void)

{

/* Enable the clock for I2C0 */

I2C0ModuleClkConfig();

I2CPinMuxSetup(I2C_0);

/* Put i2c in reset/disabled state */

I2CMasterDisable(SOC_I2C_0_REGS);

/* Disable auto Idle functionality */

I2CAutoIdleDisable(SOC_I2C_0_REGS);

/* Configure i2c bus speed to 100khz */

I2CMasterInitExpClk(SOC_I2C_0_REGS, I2C_SYSTEM_CLOCK, I2C_INTERNAL_CLOCK,

I2C_OUTPUT_CLOCK);

/* Set i2c slave address */

I2CMasterSlaveAddrSet(SOC_I2C_0_REGS, I2C_SLAVE_ADDR);

/* Bring I2C out of reset */

I2CMasterEnable(SOC_I2C_0_REGS);

while(!I2CSystemStatusGet(SOC_I2C_0_REGS));

}

/*

* \brief Clear the status of all interrupts

*

* \param none.

*

* \return none

*/

void CleanupInterrupts(void)

{

I2CMasterIntClearEx(SOC_I2C_0_REGS, I2C_INTERRUPT_FLAG_TO_CLR);

}

24!

OSD335x EEPROM During Boot

Rev.1 6/11/2018!

!

Octavo!Systems!LLC!

/*

* \brief Transmits data over I2C0 bus

*

* \param none

*

* \return none

*/

void SetupI2CTransmit(unsigned int dcount)

{

I2CSetDataCount(SOC_I2C_0_REGS, dcount);

CleanupInterrupts();

I2CMasterControl(SOC_I2C_0_REGS, I2C_CFG_MST_TX);

I2CMasterStart(SOC_I2C_0_REGS);

while(I2CMasterBusBusy(SOC_I2C_0_REGS) == 0);

while((I2C_INT_TRANSMIT_READY == (I2CMasterIntRawStatus(SOC_I2C_0_REGS)

& I2C_INT_TRANSMIT_READY)) && dcount--)

{

I2CMasterDataPut(SOC_I2C_0_REGS, dataToSlave[tCount++]);

I2CMasterIntClearEx(SOC_I2C_0_REGS, I2C_INT_TRANSMIT_READY);

}

I2CMasterStop(SOC_I2C_0_REGS);

while(0 == (I2CMasterIntRawStatus(SOC_I2C_0_REGS) & I2C_INT_STOP_CONDITION));

I2CMasterIntClearEx(SOC_I2C_0_REGS, I2C_INT_STOP_CONDITION);

}

/*

* \brief Receives data over I2C0 bus

*

* \param dcount - Number of bytes to receive.

*

* \return none

*/

void SetupReception(unsigned int dcount)

{

unsigned int num_addr_bytes = 2;

// Transmit Address Bytes

I2CSetDataCount(SOC_I2C_0_REGS, num_addr_bytes);

CleanupInterrupts();

I2CMasterControl(SOC_I2C_0_REGS, I2C_CFG_MST_TX);

I2CMasterStart(SOC_I2C_0_REGS);

while(I2CMasterBusBusy(SOC_I2C_0_REGS) == 0);

while((I2C_INT_TRANSMIT_READY == (I2CMasterIntRawStatus(SOC_I2C_0_REGS)

& I2C_INT_TRANSMIT_READY)) && num_addr_bytes--)

{

I2CMasterDataPut(SOC_I2C_0_REGS, dataToSlave[tCount++]);

I2CMasterIntClearEx(SOC_I2C_0_REGS, I2C_INT_TRANSMIT_READY);

}

I2CMasterStop(SOC_I2C_0_REGS);

while(0 == (I2CMasterIntRawStatus(SOC_I2C_0_REGS) & I2C_INT_ADRR_READY_ACESS));

25!

OSD335x EEPROM During Boot

Rev.1 6/11/2018

!

Octavo!Systems!LLC!

// Receive Data Bytes

I2CSetDataCount(SOC_I2C_0_REGS, dcount);

CleanupInterrupts();

I2CMasterControl(SOC_I2C_0_REGS, I2C_CFG_MST_RX);

I2CMasterStart(SOC_I2C_0_REGS);

/* Wait till the bus if free */

while(I2CMasterBusBusy(SOC_I2C_0_REGS) == 0);

/* Read the data from slave of dcount */

while((dcount--))

{

while(0 == (I2CMasterIntRawStatus(SOC_I2C_0_REGS) & I2C_INT_RECV_READY));

dataFromSlave[rCount++] = I2CMasterDataGet(SOC_I2C_0_REGS);

I2CMasterIntClearEx(SOC_I2C_0_REGS, I2C_INT_RECV_READY);

}

I2CMasterStop(SOC_I2C_0_REGS);

while(0 == (I2CMasterIntRawStatus(SOC_I2C_0_REGS) & I2C_INT_STOP_CONDITION));

I2CMasterIntClearEx(SOC_I2C_0_REGS, I2C_INT_STOP_CONDITION);

}

/******************************************************************************

** UART FUNCTION DEFINITIONS

******************************************************************************/

/*

* \brief This function is used to initialize and configure UART Module.

*

* \param none.

*

* \return none

*/

void setup_UART(void)

{

volatile unsigned int regVal;

/* Enable clock for UART0 */

regVal = (HWREG(SOC_CM_WKUP_REGS + CM_WKUP_UART0_CLKCTRL) &

~(CM_WKUP_UART0_CLKCTRL_MODULEMODE));

regVal |= CM_WKUP_UART0_CLKCTRL_MODULEMODE_ENABLE;

HWREG(SOC_CM_WKUP_REGS + CM_WKUP_UART0_CLKCTRL) = regVal;

UARTStdioInit();

}

!

26!

OSD335x EEPROM During Boot

Rev.1 6/11/2018!

!

Octavo!Systems!LLC!

9 Appendix B: hsi2cEeprom.lds