AES 7880-A UHF Data Transceiver Module User Manual Manual

AES Corporation UHF Data Transceiver Module Manual

Manual

AES 7880-AUHFDATA TRANSCEIVERUSER MANUALDecember 9, 2004Notice:The exterior of any product containing this device must contain the followinglabel:“Contains FCC ID : L9N-7880-A”Warning:This device must be professionally installed with appropriate power supplyand antenna in order to ensure proper operation. For outdoor applications, theantenna gain must not exceed 10 dBi. For indoor applications, the antenna gainmust not exceed 2.2 dBi.Warning:This device may not be modified by the user. Any modifications notexpressly approved by AES Corporation could void the user’s authority to operatethe equipment.Warning:For FCC RF exposure compliance purpose, this device may not beincorporated into any product which operates within 50 cm of a person undernormal operation.
1.0 DescriptionThe AES Model 7880-A UHF Data Transceiver permits data to be transmitted inthe 421 ~ 470 MHz band of frequencies. The maximum output power is 1 W. The datarate is 9600 baud. The 7880-A interfaces with an embedded microprocessor using asimple 4-wire serial Programming Port. The operating parameters are set by AESapproved software.B2.0 SignalsThe 7880-A has 20 pins, consisting of 2 rows of 10 pins each. The followingdiagram (bottom view) shows the pin numbering scheme:The following table lists the signal pins and their function:Pin Name Function19 PSEL Select Programming Port (active low)18 PCLK Serial Clock for Programming Port17 PDI Data Input for Programing Port16 PDO Data Output from Programming Port2DCLK Data Clock for Synchronous Data3DIO Data Input/Output for Synchronous Data5VCC Power (+5 volts, 900 mA max)1GND Ground8 “10 “11 “13 “20 “Pin 1Pin 20
3.0 CalibrationThe 7880-A has a single adjustment – the Crystal Oscillator frequency. In orderto adjust the Crystal Oscillator frequency, a suitable frequency counter must be attachedto the antenna port. With the 7880-A set to transmit, using Manchester coding, theCrystal Oscillator may be adjusted until the average frequency measured by thefrequency counter corresponds to the desired center frequency. The average frequencyshould be set to within 300 Hz of the desired value. Note: The frequency counter mustbe capable of measuring up to 470 MHz with an accuracy of 100 Hz in order to ensureproper calibration of the 7880-A.4.0 Device ProgrammingThe operation of the 7880-A is controlled by the Programming Port. The protocolconforms to the Serial Peripheral Interface (SPI), originated by Motorola. The interfaceoperates in a full duplex manner, with data shifted into the PDI pin at the same time asdata is shifted out on the PDO pin. Data transfer cycles are initiated by the low-goingtransition of the PSEL pin; individual data bits are synchronized to the PCLK pin.5.0 Data CommunicationThe DIO pin is bidirectional. When the 7880-A is in transmit mode, the DIO pinbecomes an input for the data to be transmitted. When the 7880-A is in receive mode, theDIO pin becomes an output. In both cases, the data is synchronized to the DCLK pin.

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