Expand: FM/AM Radio 1.0
Expand: FM/AM Radio 1.0 datasheet — tuner, audio amplifiers, I²C map, audio path, and connectors.
Datasheet for Expand: FM/AM Radio 1.0, the Attaky FM/AM receiver Expand module. For the user guide, see the FM/AM Radio manual. System-wide pin maps and the global I²C address table are on Frame & Connections.
Features
- Integrated AM/FM software-defined-radio tuner — FM 65–108 MHz, AM (LW / MW / SW), FM stereo with RDS / RBDS
- Analog FM / AM reception with digital-IF (SDR) demodulation; no HD Radio / DRM
- Talks to the host over I²C for control and I²S for digital audio
- Onboard headphone amplifier and a separate speaker amplifier
- Automatic speaker/headphone switching in hardware — no firmware involvement
- A detachable, telescoping radio antenna
Components
| Part | Role | Interface |
|---|---|---|
| TEF6687 | AM/FM tuner | I²C 0x64 + I²S |
| MAX97220AETE+T | Headphone amplifier (auto speaker/headphone switching) | Analog audio |
| TPA6211A1DGNR | Speaker amplifier | Analog audio |
Specifications
| Item | Value |
|---|---|
| Tuner | TEF6687 (software-defined radio) |
| Bands | FM, plus AM (LW / MW / SW) |
| FM frequency range | 65–108 MHz (OIRT / Japan / Europe / US) |
| FM features | Stereo, RDS / RBDS |
| Demodulation | Analog FM / AM, digital-IF (SDR) — no HD Radio / DRM |
| Control interface | I²C (slave address 0x64) |
| Audio interface | I²S from the host |
| Antenna connector | SMA — module port female; antenna SMA male (detachable) |
| Headphone amp | MAX97220AETE+T |
| Speaker amp | TPA6211A1DGNR |
Radio
- Tuner — TEF6687 (I²C
0x64), an integrated AM/FM tuner with FM coverage of 65–108 MHz. The host sets the band and frequency over I²C; digital audio reaches the module over I²S.
Audio
The host streams audio to the module over I²S; the tuner feeds two amplifiers on board:
- Headphone — MAX97220AETE+T. Drives the headphone output and detects the headphone jack. Speaker/headphone selection is automatic in hardware — when headphones are inserted the speaker output mutes — so the firmware does not control the switch.
- Speaker — TPA6211A1DGNR. Drives the onboard speaker.
I²C address map (on-board)
| Address | Device |
|---|---|
0x64 | TEF6687 AM/FM tuner |
Connectors & power
FM/AM Radio attaches to a Core at the back of the build through the board-to-board (BTB) connector — it has no top, side, or bottom expansion IO. Each chip pin lands on a BTB position. The two audio amplifiers (MAX97220 headphone, TPA6211 speaker) are analog-only and carry no BTB signal pins; they sit between the tuner and the headphone / speaker outputs.
| Chip | Pin | Connector |
|---|---|---|
| TEF6687 (tuner) | SCL | M-BTB44 |
| TEF6687 (tuner) | SDA | M-BTB45 |
| TEF6687 (tuner) | I2S_BCK | M-BTB31 |
| TEF6687 (tuner) | I2S_WS | M-BTB32 |
| TEF6687 (tuner) | I2S_SD_1 | M-BTB39 |
| TEF6687 (tuner) | GPIO1 | M-BTB27 |
For the complete connector pin map (every BTB position) and the system-wide I²C table, see Frame & Connections.
Mechanical
| Item | Value |
|---|---|
| Module body | 66 × 46 mm |
| Thickness | 10.5 mm |
| Height, antenna retracted | 220 mm |
| Antenna, extended length | 752 mm |
Operating conditions
| Item | Value |
|---|---|
| Operating temperature | 0–40 °C (32–104 °F) |
| Water resistance | None — not waterproof, no IP rating |
Keep it dry, out of direct sunlight, and away from prolonged heat — do not leave it in a parked car.