Grove

Main menu key: e

External-module shelf: I2C (FM radio, NFC, bus scan) and UART (GPS; also Cap LoRa-1262 GNSS on Adv) on the left Grove / Cap bus. Up to 8 cards per page; number keys restart at 1 on the current page; letter shortcuts work from any page. ESC / GO returns a child to this shelf; press again on the shelf to return to the main menu.

This page covers wiring, behavior, and source APIs for chips the firmware already drives. Radio: Radio. NFC: NFC. GPS: GPS. Scan: I2C Scan. CC1101 driver code remains, but the shelf entry is hidden for now (unfinished).

Screenshots

Shelf

Children

Key	Child	Bus	Chip	Role
1 / r	RADIO	Grove I2C	TEA5767 / RDA5807M	FM, seek, station list; RDA also has volume / RDS
2 / e	EXI2	Grove I2C	any ACK	List addresses with a likely chip name and role
3 / n	NFC	Grove I2C	ST25R3916 (Unit NFC)	Read / write 13.56 MHz, NDEF / stored-card emulate, history
4 / g	GPS	Grove UART or Cap UART	AT6668 (Unit / Cap LoRa GNSS)	Live / speed / sky / record; auto-detect source

Shortcuts

Key	Action
1–8	Open the child on the current page
r / e / n / g	Jump to RADIO / EXI2 / NFC / GPS
[ ] / arrows	Flip the shelf (when there are more than 8 items)
ESC / GO	Child → shelf → main menu
h	Help inside a child (the shelf has none)

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Hardware

Cardputer-ADV exposes two common expansion ports. This shelf groups them, but the protocols differ — do not mix 5 V onto a 3.3 V radio.

Left Grove (Ex_I2C)

HY2.0-4P rubber socket on the left with the screen facing you and the keyboard at the bottom. Firmware object: M5Cardputer.Ex_I2C. Related apps call Ex_I2C.begin() (boot only setPorts; without begin a Grove scan is empty).

Order (top→bottom)	Pin	Role
1	GND	Ground
2	5V	Power (for 5 V modules)
3	G2	SDA
4	G1	SCL

Match FM modules by silkscreen SDA / SCL / VCC / GND, not by counting pins left-to-right. Audio comes from the module 3.5 mm jack, not the Cardputer speaker.

Fallback: if Grove has no FM chip, Radio retries M5Cardputer.In_I2C (EXT G8=SDA / G9=SCL).

Rear EXT14 (CC1101 SPI)

Shares SPI with microSD; chip-select is separate. Firmware uses FSPI with SPISettings(2 MHz, MSBFIRST, SPI_MODE0).

Module pin	GPIO	Role
VCC	3.3 V	3.3 V only — never 5 V
GND	GND	Ground
CSN	G13	Chip select
SCK	G40	SPI clock
MOSI	G14	Host out
MISO	G39	Host in
GDO0	G15	RX/TX done IRQ
GDO2	G5	Optional carrier detect (wired; RST is NC)

EXT14 5VIN / 5VOUT are 5 V — do not use them as CC1101 VCC.

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Chips in this firmware

TEA5767 (FM)

Item	Value
Bus	I2C address 0x60
Port	Grove G2/G1 first, then In_I2C G8/G9
Frequency unit	0.01 MHz (9850 = 98.50 MHz)
Bands	Europe 87.50–108.00 MHz; Japan 76.00–91.00 MHz
Step	0.10 MHz
Volume	No chip volume — use the headphone knob
Probe	scanID(0x60); writes a 5-byte register block
Source	include/tea5767.h, src/tea5767.cpp

Features: tune, mute, force mono, soft mute, high-cut (HCC), stereo noise cancel (SNC), 50/75 µs de-emphasis, high/low-side injection (HLSI), hardware seek (SM/SUD/SSL), L/R channel mute, standby. Level ADC updates only after a register write; the UI periodically calls kickAdc().

RDA5807M (FM + RDS)

Item	Value
Bus	I2C sequential 0x10, random 0x11
Port	Same as TEA5767
Frequency unit	0.01 MHz
Bands	87–108 / 76–91 / 76–108 / 65–76 / 50–76 MHz
Spacing	25 / 50 / 100 / 200 kHz
Volume	Chip 0–15
Probe	Read register 0x00; chip-ID high byte is 0x58
Source	include/rda5807m.h, src/rda5807m.cpp

Features: tune / hardware seek, mute, output high-Z, bass boost, soft mute, soft blend, AFC, RDS/RBDS (PS, RT, CT, AF), optional I2S. An I2C scan write-probe can wake the RF; afterwards silence() writes 0x02 = 0 (ENABLE off, audio high-Z).

FmTuner::begin() probes RDA first, then TEA. If both sit on the bus, RDA wins.

CC1101 (433 MHz Sub-GHz, shelf entry hidden)

Driver and EXT14 wiring remain, but the Grove shelf card is hidden (unfinished). Do not assume G13 / G15 are free for CC1101 while Cap LoRa GNSS is in use.

Item	Value
Bus	SPI (not I2C), RadioLib
Port	EXT14, table above
Default frequency	433.92 MHz
Range	387.00–464.00 MHz, 0.25 MHz step
Modulation	begin(freq, 4.8 kbps, 4.8 kHz deviation, 58 kHz RX BW, 10 dBm, 32-bit preamble)
Source	include/app_cc1101.h, src/app_cc1101.cpp

Features (code present): init / re-init, send test packet CP-<seq>, listen ~3 s, arrow keys change frequency, RSSI refresh every 500 ms. No chip → NOT FOUND. Leaving the App calls standby().

I2C scan map (guesses only)

Scan range 8–119 (0x08–0x77). Green dot = known map, gray = unknown (-- / unknown). The ExI2 table is a likely Grove / Unit match, not a driver list. External chips with real drivers are mainly the FM tuners, NFC, GPS (and the hidden CC1101).

Address	Likely chip	Role
0x10 / 0x11	RDA5807M	radio
0x18	ES8311	codec
0x23	BH1750	light
0x26	MiniScale	weight
0x29	VL53L0X	ToF
0x34	TCA8418	keyboard
0x3C / 0x3D	SSD1306	OLED
0x41	8Encoder	encoder
0x43	8Angle	angle
0x44	SHT3x	ENV
0x48	ADS1115	ADC
0x50	EEPROM	memory
0x51	BM8563	RTC
0x57	UnitUS	sonar
0x5A	MLX90614	NCIR
0x5F	CardKB	keyboard
0x60	TEA5767	radio
0x61	PbHub	hub
0x68 / 0x69	BMI270	IMU
0x70	QMP6988	ENV
0x76 / 0x77	BMP280	ENV

Onboard confirmed (Hardware Test → InI2): 0x18 ES8311, 0x34 TCA8418, 0x68 BMI270.

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App APIs

Same enter / leave / update / handle convention as other apps; Help uses close* / is*HelpVisible.

app_ex_i2c (shelf)

void enterExI2cApp();
void leaveExI2cApp();
void updateExI2cApp();
void handleExI2cApp(const Keyboard_Class::KeysState& status);
bool handleExI2cBack();          // child → hub; false if already on hub
bool closeExI2cHelp();           // delegates Radio / scan / CC1101 / NFC / GPS Help
bool isExI2cHelpVisible();
bool isExI2cRadioActive();       // screenshot slug
bool isExI2cCc1101Active();

main.cpp calls handleExI2cBack() before leaving for the main menu. Leaving the shelf stops Radio, mutes any FM on the bus, and stands by CC1101 / NFC / GPS.

app_radio

void enterRadioApp();
void leaveRadioApp();
void silenceFmRadioOnBus(m5::I2C_Class& bus); // mute + standby after a scan probe
void updateRadioApp();
void handleRadioApp(const Keyboard_Class::KeysState& status);
bool closeRadioHelp();
bool closeRadioStations();
bool closeRadioSeek();
bool isRadioHelpVisible();

app_i2c_scan

void drawI2cScanApp(m5::I2C_Class& bus, const char* title, bool internal_bus);
void handleI2cScanApp(const String& key, m5::I2C_Class& bus,
                      const char* title, bool internal_bus);
bool closeI2cScanHelp(m5::I2C_Class& bus, const char* title, bool internal_bus);
bool isI2cScanHelpVisible();
void resetI2cScanHelp();

The Grove shelf passes M5Cardputer.Ex_I2C, "ExI2", false. Hardware Test InI2 / ExI2 share the same functions. drawI2cScanApp runs bus.scanID(found) then silenceFmRadioOnBus(bus).

app_cc1101

void enterCc1101App();
void leaveCc1101App();
void updateCc1101App();
void handleCc1101App(const Keyboard_Class::KeysState& status);
bool closeCc1101Help();
bool isCc1101HelpVisible();

Key	Action
r	begin again at the current frequency
t	Send CP-<seq>
l	startReceive(), ~3 s timeout
Arrows	±0.25 MHz
h	Wiring / key Help

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Driver APIs

The Radio App talks to both FM chips through FmTuner; chip-specific extras still come from tea() / rda(). Frequencies are always 0.01 MHz.

FmTuner (include/fm_tuner.h)

bool begin(m5::I2C_Class& bus);          // RDA → TEA
void detach();
static void silenceIfPresent(m5::I2C_Class& bus);

Chip chip() const;                       // None / Tea5767 / Rda5807m
bool isRda() const;
const char* chipName() const;

uint16_t freqMin() const;
uint16_t freqMax() const;
uint16_t freqStep() const;
void setFrequency(uint16_t freq_centi, bool wait_settle = true);
bool readStatus(Status& out);            // RSSI scaled to 0–15
void refreshSignal();                    // TEA: kickAdc

void setMute(bool on);
void setMono(bool on);
void setStandby(bool on);
void startSearch(bool up);
void abortSearch();

Tea5767& tea();
Rda5807m& rda();

Status: freq_centi, rssi (0–15), raw_rssi, quality, stereo, ready, band_limit, valid_station, rds_ready / rds_synced.

TEA-only setters (no register writes in RDA mode): setJapanBand, setDeemphasis75, setHighSideInjection, setSoftMute, setHighCut, setStereoNoiseCancel, setSeekStop, setChannelMute.

Tea5767

bool begin(m5::I2C_Class& bus);
bool probe() const;
bool silence(m5::I2C_Class& bus);

void setFrequency(uint16_t freq_centi, bool wait_settle = true);
uint16_t getFrequency();
bool readStatus(Status& out);
void kickAdc();
void startSearch(bool up);
void abortSearch();

void setMute(bool on);
void setMono(bool on);
void setSoftMute(bool on);
void setHighCut(bool on);
void setStereoNoiseCancel(bool on);
void setJapanBand(bool on);
void setDeemphasis75(bool on);
void setHighSideInjection(bool on);
void setSeekStop(SeekStop level);     // Low / Mid / High
void setChannelMute(ChannelMute ch);  // Off / Left / Right
void setStandby(bool on);
void setPort1(bool high);
void setPort2(bool high);

Rda5807m

bool begin(m5::I2C_Class& bus, bool reset = true);
bool probe(uint16_t* chip_id = nullptr);
bool initialize();
bool softReset();
bool silence(m5::I2C_Class& bus);
bool setStandby(bool standby);

bool setBand(Band band);
bool setSpacing(Spacing spacing);
bool setFrequency(uint16_t freq_centi, bool wait = true, uint32_t timeout_ms = 500);
bool startTune(uint16_t freq_centi);
bool pollTune(Status* status = nullptr);
bool startSeek(bool up);
bool abortSeek();
bool waitSeek(uint32_t timeout_ms = 5000, Status* status = nullptr);

bool setMute(bool mute);
bool setMono(bool mono);
bool setHighZ(bool high_z);
bool setVolume(uint8_t volume);          // 0–15
bool setBass(bool enabled);
bool setDeemphasis50(bool use_50us);
bool setSoftMute(bool enabled);
bool setSoftBlend(bool enabled);
bool setAfc(bool enabled);
bool setSeekThreshold(uint8_t threshold);
bool setSeekWrap(bool wrap);
bool setRds(bool enabled);
bool setRbds(bool enabled);
bool pollRds(RdsGroup* group = nullptr);

const char* programService() const;      // PS
const char* radioText() const;           // RT
uint16_t programId() const;              // PI

Diagnostics: readRegister / writeRegister only for public registers; writes limited to 0x02–0x08.

RadioLib CC1101

What this firmware actually calls (not the full RadioLib surface):

g_radio.begin(freq_mhz, 4.8f, 4.8f, 58.0f, 10, 32);
g_radio.setFrequency(freq_mhz);
g_radio.transmit(payload);
g_radio.startReceive();
g_radio.available();
g_radio.readData(buf, len);
g_radio.getRSSI();
g_radio.standby();

m5::I2C_Class

Globals: M5Cardputer.Ex_I2C, M5Cardputer.In_I2C. Scan and drivers both sit on this layer:

Method	Use
begin()	Init Grove / internal port
isEnabled()	Whether init ran
scanID(bool result[120]) / scanID(addr)	Full scan or single-address probe
getSDA() / getSCL()	Current pins
writeRegister* / readRegister*	Register access

See api/M5Unified.md (I2C_Class) in the repo for the lower-level list.

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Usage

1. Main menu e opens Grove. Warm-green cards: 1 RADIO, 2 EXI2, 3 NFC, 4 GPS (CC1101 entry hidden for now).
2. Radio: plug a ready-made 4-pin board into the left Grove (G2=SDA, G1=SCL); headphones into the module jack. No chip → NO MOD. Keys: Radio.
3. Scan: open EXI2 after plugging a device, or Hardware Test 8. r rescans. Probing FM addresses may briefly unmute; the App mutes and standbys afterwards.
4. NFC: Unit NFC (ST25R3916) on the left Grove. See NFC.
5. GPS: Grove AT6668 Unit, or Adv + Cap LoRa-1262 GNSS; auto-detect on enter. See GPS.
6. Leaving a child or the whole shelf stops FM / NFC / GPS so ports are not left busy.