Protocol
With the exception of transparent mode, the radio communicates with the user hardware via a set of formatted commands and responses.
All commands and responses take the following form:
| Field | Bytes | Description |
| Prefix | 1 | Constant $AA |
| PcktType | 1 | Type of packet to follow. |
| PayLdLen | 2 | The length of the following payload in bytes (n) |
| PayLdData | n | The packet payload itself. See the command appendix. |
| Checksum | 1 | A verification checksum |
| Suffix | 1 | Constant $55 |
Valid PcktTypes are as follows:
| PcktType | Class | Description | |
| $00 – $0F | AckData | Guaranteed-delivery packets | |
| $10 – $1F | NoAckData | No acknowledgement packets | |
| $20 – $2F | Ack | Acknowledgement packets | |
| $30 | QuerySigStr | Test signal strength command | |
| $31 | SigStr | Signal strength response | |
| $80 | ReadMem | Read data from radio's RAM or EEPROM memory | |
| $81 | WriteMem | Write data to radio's RAM or EEPROM memory | |
| $82 | SweepFreq | Read signal strengths from a range of frequencies | |
| $83 | ReadModel | Read radio's model string | |
| $84 | ReadFirm | Read radio's firmware version | |
| $85 | ReadSerial | Read radio's serial number | |
| $86 | Success | Successful command execution reply | |
| $87 | Failure | Failed command execution reply | |
| $88 | SetMode | Set the radio's current mode | |
| $89 | WriteFlash | Write data to radio's Flash memory | |
| $8A | ListenSigStr | Listen to communications and report signal strengths | |
| $8B | RestartRadio | Reset the radio and reload settings from EEPROM | |
| $8C | SetDebug | Enable one of the debugging modes | |
| $8D | ReadRSSI | Read a raw RSSI value | |
| $8E | FlushQueue | Report when all packets have been processed |
The Checksum is calculated by totaling the byte codes in the PcktType, PayLdLen, and the PayLdData fields. Only the low eight bits of the total are kept.
Example:
As you can see in the command definition, the SetMode command has a PcktType of $88 and a payload of a single byte (Mode). A Mode of $01 indicates a switch to mixed-on mode. So to switch to the mixed-on mode you would send the following byte codes to the serial port:
$AA, $88, $01, $00, $01, $8A, $55
Note that the Checksum of $8A = $88 + $01 + $00 + $01.
The radio should respond with:
$AA, $86, $03, $00, $88, $00, $00, $11, $55
This indicates Successful processing (PcktType $86) of a SetMode command (PcktType $88) with zero bytes of additional data.
The Checksum ($11) is the low eight bits of $86 + $03 + $00 + $88 + $00 + $00 = $111.
