Removing the CPU
I took the plunge, removed the main MCU and just soldered wires to the pads (I did not have a rework station, so I used my soldering iron. I just ordered a rework station from sparkfun). Everything seems to work ok and I am able to fully configure the RDA chip and set auto sq, freq, etc.
Here is what I am doing with the pins.
PC1 -> RX power, I am feeding 3.3V for this.
P56 -> U/V mode. I set it to 0 for VHF and 3.3V for UHF
P66 -> TX power. I am setting this to 3.3v since 0 is to activate
Here is the protocol message that I gathered which seems to work well (the first
arg is register the next one is value and then description)
Initial Settings
0x30 0x0001 Reset all registers to default values
0x30 0x0004 same as pdn (dont sleep)
0x04 0x0FD0 24-28Mhz
0x09 0x032C high voltage of GPIO is 2.7V, 0x03AC high votlage of GPIO is more
then 3.0V, based on power voltage
0x0B 0x1A10
0X2B 0x32C8 26Mhz xtal
0x2C 0x1964 adc clk for 26Mhz xtal
0x32 0x627C
0x33 0x0AF2
0x47 0x1AEA for 12.5KHz or 0x2C2F for 25kHz
0x4E 0x293A
0x54 0x1D40 for 12.5KHz or 0x1D4C for 25kHz
0x56 0x0652
0x6E 0x062D for 25kHz no register for 12.5KHz
0x71 0x6C1E for 12.5Khz or 0x70 0x1029 for 25Khz
0x85 0x001F RFpower is 8dBm, ACP is -63dB in 12.5KHz and -65dB in 25KHz
0x0018 RFpower is 6dBm, ACP is -64dB in 12.5Khz and -66dB in 26KHz
0x0017 RFpower is -3dBM, ACP is -68dBc in 12.5KHz and -68dBc in 25KHz
0x30 0x0006 for 12.5KHz or 0x3006 for 25Khz
Delay a minimum of 100ms
To RX
0x29 Freq
0x2A Freq
0x30 0x0006 for 12.5KHz or 0x3006 for 25Khz
0x30 0x0026 for 12.5KHz or 0x3026 for 25Khz
To RX with auto Sq
0x29 Freq
0x2A Freq
0x48 and 0x49 setting Sq open and shut threshold
0x30 0x0006 for 12.5KHz or 0x3006 for 25Khz
0x30 0x002E for 12.5KHz or 0x302E for 25Khz
To RX with mute
0x29 Freq
0x2A Freq
0x30 0x0006 for 12.5KHz or 0x3006 for 25Khz
0x30 0x00A6 for 12.5KHz or 0x30A6 for 25Khz