ELPRO Technologies S2900 Wireless Modem Module User Manual 945U E

Incorrect termination of the supply wires may cause internal damage. Before turning the power on double-check ALL

connections by referring to this User Manual.

terminated.

Operate the equipment near electrical blasting caps or in an explosive atmosphere. 

All equipment must be properly grounded for safe operations. All equipment should be serviced only by a qualified

ELPRO staff only.

Part 90 – This device has been type accepted for operation by the FCC in accordance with Part90 of the FCC rules

(47CFR Part 90). See the label on the unit for the specific FCC ID and any other certification designations.

Exposure to RF energy is an important safety consideration. The FCC has adopted a safety standard for human

exposure to radio frequency electromagnetic energy emitted by FCC regulated equipment as a result of its actions in

Docket 93-62 and OET Bulletin 65 Edition 97-01.

THIS DEVICE COMPLIES WITH PART 15 OF THE FCC RULES. OPERATIONIS SUBJECT TO THE FOLLOWING

TWO CONDITIONS: (1) THIS DEVICE MAY NOT CAUSE HARMFUL INTERFERENCE, AND (2) THIS DEVICE

MUST ACCEPT ANY INTERFERENCE RECEIVED, INCLUDING INTERFERENCE THAT MAY CAUSE UNDESIRED

NOTE: THE GRANTEE IS NOT RESPONSIBLE FOR ANY CHANGES OR MODIFICATIONS NOT EXPRESSLY

APPROVED BY THE PARTY RESPONSIBLE FOR COMPLIANCE. SUCH MODIFICATIONS COULD VOID THE

l'utilisateur de l'appareil doit accepter tout brouillage radioélectrique subi, même si le brouillage est susceptible d'en

compromettre le fonctionnement.

ELPRO S2900 radio module is designed as a reusable module for use with future development of ELPRO products.

The module is limited for use by ELPRO only. This module is not to be made available for third party use or in any

OEM arrangements.

The integrator is responsible for ensuring that the end-user has no manual instruction to remove or install module.

The separate approval is required for all other operation configurations, including portable configuration with respect to

Part 2.1093 and different antenna configuration.

CHAPTER 3 - Main Host Interface .................................. 5

Alternate Host Interface ................................................... 6

Production Interfaces ....................................................... 6

CHAPTER 4 - OPERATION ............................................. 6

CHAPTER 5 - Locale ..................................................... 12

CHAPTER 6 - Interface Pin Description ........................ 12

Main Host Interface Pin Description ............................... 12

CHAPTER 7 - Protective Earthing Point ........................ 13

CHAPTER 8 - SPECIFICATIONS .................................. 13

section.

The interface between the radio and the controlling equipment is specified by the electrical and timing information

The physical interface consists of the following electrical signals:

• BYTE_READY Indication from radio that data has been received

SCK Idles high. Data changes on the falling edge of SCK, and is sampled on the rising edge of SCK. Eight data bits

the specified frequency. Once the lead-in transmission is complete, the radio begins transmission of the frame

synchronization (SYNC) byte, and simultaneously raises the BYTE_READY line. When the BYTE_READY line is

raised, the controller lowers the SELECT line, and transfers the first byte of data to be sent via the SPI. The radio

lowers the BYTE_READY line when the controller lowers the SELECT line. As the radio completes transmission of the

SYNC byte, it retrieves the first byte of data from the SPI, and again raises the BYTE_READY line. This repeats until

all data is sent. At this time, the controller does not lower the SELECT line, and the radio leaves the BYTE_READY

line high until transmission of the data frame is complete.

The radio raises the BYTE_READY signal as soon as a radio lead-in is detected. A byte containing the value 0xFF

(Lead-in Found) is transferred to indicate that the radio channel is busy. When the SYNC byte is received over the

radio channel, the radio again lowers the BYTE_READY line. The next byte transferred contains the measured signal

strength (RSSI) of the incoming radio signal. If the lead-in signal is lost, or if the SYNC byte is not detected, the next

byte contains the value 0xFE (Lead-in Lost). Subsequent bytes are the data received over the radio.

adaptations are provided to assist in the case of slower host devices.

In the case of 19,200 baud rate, during data transmission, the time between the start of the SYNC word and the start

of the first data byte is shorter than the time between subsequent data bytes. For this reason, the Sync word is

extended to 44 bits when the baud rate is 19,200. This allows the host to respond with the first data byte within the

same time required for subsequent data bytes. (486 uSec).

When the radio detects lead-in, it is possible that “Lead In Lost” may be detected within 110 uSec of the “Lead In

resulting in an overrun condition. If the baud rate is 19,200 baud then the radio delays (up to) an additional 376 uSec

before sending the “Lead In Lost” message. This delay is shorter if the previous SPI transfer has completed.

(0xFF). In this case, the radio will abort the radio reception, and begin performing the requested transmission. Once

the transfer of the “lead-in-found” code is complete, the radio will ignore subsequent requests from the controller until

the frame reception is complete, or the lead-in is lost (RSSI byte = 0xFE).

The Received signal strength is transferred from the radio at the beginning of the incoming data frame. It is also

possible for the Controller to request the current signal strength when the radio is not receiving data. To do this, the

controller sends the code 0xEE (Request received signal strength). The radio measures the signal strength on the