EV9900 Datasheet, PDF (6/27 Pages) CML Microcircuits – Evaluation Kit

Evaluation Kit for CMX990
EV9900
3.3 Operation
The CMX990 is a complex RF and Baseband Modem IC. It is recommended that the user
familiarise themselves with the datasheet of this device prior to attempting to use the EV9900.
To use the EV9900 the user will need a mechanism to send and receive data and commands via
the 8bit parallel host µController interface on the CMX990, which is brought out on connector J13
on the EV9900. The CMX990 datasheet gives details of the registers and commands. To
operate the CMX990, some typical command sequences are given below:
Receive Mode
The following example C code shows a typical configuration for reception.
register_write(POWER_UP_2, 0x08); //Reset
register_write(POWER_UP_2, 0x01); //Vbias on
register_write(POWER_UP_1, 0xEE); //Clock+BB+Vreg,+Rx:on & Opamps+Tx:off
register_write(POWER_UP_2, 0xF1); //DACs on
register_write(AUX_DAC_1_MSB,169); //AFC to mid rail (1.65V)
//Set up synths:
set_main_synth(0x8600,0x011C10); //1818HMz, high side, Rx Freq=864MHz
//(assuming ref 19.2MHz & comp 12.5kHz)
set_aux_synth(0x80C0,0x0708);
//180HMz
//(assuming ref 19.2MHz & comp100kHz)
register_write(CONTROL, 0xE9);
//AGC max gain & run, IQ offset fine,
//AFC Slow, PLL Narrow
register_write(MODE, 0xD2);
//IRQ enabled, scrambler enabled,
//INV bit enabled, Main ADC enabled, Rx mode
register_write(POWER_UP_2,0xF5); //Turn LNA on.
register_write(COMMAND, 0x60);
//Acquire DC offset & AFC
//DelayBy(90000);
//Wait for Offset to complete
Following the above routines the user may initiate reception of data using the modem task
commands in Command register ($01).
© 2005 CML Microsystems Plc
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