This document contains experimentally-observed behavior of the ADB protocol of the LaCie FM Radio. It contains enough information to satisfactorally emulate the device, however, a few unknowns exist.
The FM Radio's default address is 0x7 and its default handler ID is 0x79.
Register 1 sets the volume and tone controls and is three bytes in length.
| Bit | Description |
|---|---|
| 23-16 | Volume, apparently set in increments of 0x11 by the application |
| 15 | Always zero |
| 14-12 | Treble |
| 11 | Always zero |
| 10-8 | Bass |
| 7 | Mute, active high |
| 6-5 | Sound fading, 0 = normal, 1 = low, 2 = medium, 3 = high |
| 4-1 | Undetermined, apparently always zero |
| 0 | Undetermined, initially zero but always set high by the application |
Talk 1 has a fourth byte appended which is the firmware revision of the FM Radio.
Register 2 sets the FM station and is three bytes in length. Talk 0 has a response (apparently immediately, but possibly only when tuning is finished) to every Listen 2 that is identical to Talk 2.
In a Listen 2 command, the first byte seems to always be 0x41. In a Talk command, the bits of the first byte are as follows:
| Bit | Description |
|---|---|
| 7 | FM stereo indicator, active high |
| 6-1 | Undetermined, apparently always zero |
| 0 | Signal strength indicator, active high |
The second and third bytes indicate the FM station. Starting from a base of -10.7 MHz, the following values are added to it:
| Bit | Value |
|---|---|
| 15 | Undetermined, always zero |
| 14 | Undetermined, always zero |
| 13 | 102.4 MHz |
| 12 | 51.2 MHz |
| 11 | 25.6 MHz |
| 10 | 12.8 MHz |
| 9 | 6.4 MHz |
| 8 | 3.2 MHz |
| 7 | 1.6 MHz |
| 6 | 800 kHz |
| 5 | 400 kHz |
| 4 | 200 kHz |
| 3 | 100 kHz |
| 2 | 50 kHz |
| 1 | Undetermined, always zero |
| 0 | Undetermined, always zero |