BLE HID Remote Controller

Overview

The hid_remote application implements a Bluetooth LE Remote Controller on a single Atmosic SoC. It provides:

  • HOGP - HID over GATT Profile (keyboard + consumer control reports)

  • ATVV - Android TV Voice over BLE (DMIC -> IMA ADPCM -> GATT voice stream)

  • IR/NEC - Infrared blaster driven by the Atmosic PWM FIFO driver

  • BAS - Battery Service

  • DIS - Device Information Service (PnP VID/PID)

  • OTA - MCUmgr firmware upgrade over BLE (optional, via basic_ota_bt.conf)

The application uses two cooperating SMF (Zephyr State Machine Framework) instances:

  • MMI state machine - user-facing states (idle, pairing, connected, HID ready, streaming)

  • GAP state machine - advertising lifecycle (reconnect, pairing, stop)

Supported Boards

  • ATMEVK-5205-NQK-2

Key Combinations

Press both keys:

  • HOME + BACK - immediately enter undirected pairing mode. Pairing mode remains active until the next cold boot; hibernation wakeup does not switch back to reconnect mode.

  • OK + VOL+ - delete all bonds and perform a cold reboot.

The LED stays on while a combination is active, and the individual key events are suppressed. The pairing combination does not reboot the remote.

Building

Default build:

west build -p always -b <BOARD> openair/applications/hid_remote –sysbuild -T applications.hid_remote.atm

With MCUboot OTA support:

west build -p always -b <BOARD> openair/applications/hid_remote --sysbuild -T applications.hid_remote.atm.mcuboot.ota

Flashing

west flash --no-rebuild --device <DEVICE_ID> [--jlink] [--erase_all/--erase_flash]

Configuration

Key Kconfig options (prj.conf):

Kconfig

Purpose

CONFIG_ATM_HOGP

HID over GATT Profile

CONFIG_RC_VOICE

Enable ATVV GATT service + ADPCM encoder; implies DMIC_ATM

CONFIG_DMIC_ATM

Atmosic DMIC (PDM microphone) driver (implied by RC_VOICE)

CONFIG_AUDIO_ADPCM_ENC

IMA ADPCM encoder library

CONFIG_ATM_ATVV

Android TV Voice GATT service

CONFIG_IR_NEC

NEC infrared blaster

CONFIG_BT_BAS

Battery Service

CONFIG_BT_DIS

Device Information Service

CONFIG_BT_SETTINGS

Bond persistence via NVS flash

CONFIG_RETAINED_MEM

Retain the forced-pairing marker across hibernation wakeup

CONFIG_BT_ID_MAX

Number of local Bluetooth identities (configured as 1)

CONFIG_BT_MAX_PAIRED

Maximum bonded hosts (configured as 2)

CONFIG_BT_MAX_CONN

Maximum simultaneous BLE connections (configured as 3)

CONFIG_BT_EXT_ADV_MAX_ADV_SET

Extended advertising sets for two reconnect targets and one pairing set

CONFIG_INPUT_ATM_KBD_MATRIX

Atmosic keyboard matrix input driver

Key timing constants (Kconfig):

Constant

Default

Description

RC_CONNECTION_IDLE_TIMEOUT_CS

60000 cs

Disconnect after idle (600 s)

RC_CONNECTION_READY_TIMEOUT_CS

3000 cs

HID ready watchdog (30 s)

RC_ENABLE_SLAVE_LAT_TIMEOUT_CS

3000 cs

Slave latency enable delay (30 s)

RC_AUDIO_STREAM_TIMEOUT_CS

1000 cs

Maximum voice stream duration (10 s)

CONFIG_RC_ADV0_DURATION_MS

30000 ms

Reconnect advertising window; converted to Zephyr’s 10 ms timeout units

CONFIG_RC_ADV1_DURATION_MS

6000 ms

Pairing advertising window; converted to Zephyr’s 10 ms timeout units

Advertising

The application uses one BT identity (CONFIG_BT_ID_MAX=1), supports up to two bonded hosts and up to three simultaneous BLE connections. It selects between two advertising modes:

  • Reconnect - low-duty directed advertising for each bonded host

  • Pairing - undirected, connectable, scannable advertising that broadcasts the device name

On a normal cold boot, the application starts reconnect advertising when a bond exists; otherwise it starts undirected pairing advertising. Pressing HOME + BACK overrides this selection and keeps pairing advertising active until a cold boot. The forced-pairing marker is stored in Atmosic hibernation-retained memory. Advertising interval defaults to 40 ms (0x0040 x 625 us) and is configurable via CONFIG_RC_ADV_INTERVAL_MIN / CONFIG_RC_ADV_INTERVAL_MAX in Kconfig.

Voice Pipeline

When ATVV is enabled the voice data path is:

PDM microphone -> DMIC driver -> PCM samples -> IMA ADPCM encoder -> ATVV GATT notify

The host opens the microphone by writing MIC_OPEN to the ATVV control point. The MMI transitions to MMI_S_STREAMING and calls rc_audio_stream_start(). On MIC_CLOSE or ATVV disconnect the stream stops automatically.