Serial protocol.
The serial data consists of 25 bits. 17 of those are used for the divider to the PLL, the remaining 8 to control the radio.
Format
| 2 | 2 | 2 | 2 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 4 | 3 | 2 | 1 | 0 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
|
PLL-data |
Control data |
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Bit 24 is sent first (MSB).
PLL-data
The 17 bits are calculated as follows:
IF = 45.15MHz, fref=12.5kHz, f=desired frequency, D=divider
Transmission
D = f/fref
Receiving
D = (f - IF)/fref
The result, D, consists of 16 bits, bit 17 needs to be stuffed in at pos 5. The lowest 5 bits (bit 0-4)are kept as the are, and bit 5 to bit 15 are shifted one step to the left.
| 1 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 5 | 4 | 3 | 2 | 1 | 0 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
...to this...
| 1 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | * | 0 | 0 | 0 | 0 | 0 |
| 5 | 4 | 3 | 2 | 1 | 0 | 9 | 8 | 7 | 6 | 5 | * | 4 | 3 | 2 | 1 | 0 |
...resulting in...
| 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 6 | 5 | 4 | 3 | 2 | 1 | 0 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Control bits
The 8 bits that controls the receiver:
| Bit | Function | |
| 0 | (Q1) | Not used |
| 1 | (Q2) | Not used |
| 2 | (Q3) | Not used |
| 3 | (Q4) | RF Power (J102 to PA) |
| 4 | (Q5) | /Radio mute (rear connector J101) |
| 5 | (Q6) | Squelch override. 0= SQ IFF, 1=SQ ON |
| 6 | (Q7) | PTT, TX/RX switching. 1=TX, 0=RX |
| 7 | (Q8) | External alarm switch (rear connector J101) |
Pinout microphone<->Tranceiver?