chore(v16): add support for more IMU hardware (#7482)

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

radio/src/drivers/icm42627.cpp

@@ -31,8 +31,9 @@ static etx_i2c_bus_t s_i2c_bus;
 static uint16_t s_i2c_addr;
 
 static constexpr uint32_t RESET_DELAY_MS = 150;
-static constexpr uint32_t READY_TIMEOUT_MS = 200;
-static constexpr uint32_t POWER_DELAY_MS = 20;
+static constexpr uint32_t READY_TIMEOUT_MS = 500;
+static constexpr uint32_t POWER_ON_SETTLE_US = 200;
+static constexpr uint32_t GYRO_STARTUP_DELAY_MS = 45;
 static constexpr uint32_t CONFIG_DELAY_MS = 1;
 static constexpr uint8_t BURST_READ_LEN = 14;
 
@@ -75,7 +76,10 @@ static int gyro42627Init(etx_i2c_bus_t bus, uint16_t addr)
     return -1;
   }
 
-  if (i2c_dev_ready(s_i2c_bus, s_i2c_addr) < 0) {
+  // The chip can take longer than a couple of quick retries to start
+  // acknowledging on I2C after power-up, so give the initial probe the
+  // same generous retry window used after a soft reset below.
+  if (wait_for_device_ready(READY_TIMEOUT_MS) < 0) {
     TRACE("ICM42627: device did not acknowledge on I2C");
     return -1;
   }
@@ -103,17 +107,28 @@ static int gyro42627Init(etx_i2c_bus_t bus, uint16_t addr)
     return -1;
   }
 
-  if (write_cmd(ICM42627_PWR_MGMT0_REG, ICM42627_PWR_STAGE1) < 0) {
-    TRACE("ICM42627: failed to write PWR_MGMT0 stage 1");
+  // Per datasheet section 12.6 ("Register Values Modification"), registers
+  // other than ODR/FSR/mode selects must only be changed while the
+  // accel/gyro are off. Configure the signal path here, while PWR_MGMT0
+  // still has gyro and accel powered down, then power them on last.
+  if (write_cmd(ICM42627_BANK_SEL_REG, ICM42627_BANK1) < 0) {
+    TRACE("ICM42627: failed to select register bank 1");
     return -1;
   }
-  delay_ms(POWER_DELAY_MS);
+  delay_ms(CONFIG_DELAY_MS);
 
-  if (write_cmd(ICM42627_PWR_MGMT0_REG, ICM42627_PWR_STAGE2) < 0) {
-    TRACE("ICM42627: failed to write PWR_MGMT0 stage 2");
+  if (write_cmd(ICM42627_GYRO_STATIC2_REG, ICM42627_GYRO_STATIC2) < 0) {
+    TRACE("ICM42627: failed to write GYRO_STATIC2");
+    write_cmd(ICM42627_BANK_SEL_REG, ICM42627_BANK0);
     return -1;
   }
-  delay_ms(POWER_DELAY_MS);
+  delay_ms(CONFIG_DELAY_MS);
+
+  if (write_cmd(ICM42627_BANK_SEL_REG, ICM42627_BANK0) < 0) {
+    TRACE("ICM42627: failed to restore register bank 0");
+    return -1;
+  }
+  delay_ms(CONFIG_DELAY_MS);
 
   if (write_cmd(ICM42627_GYRO_CONFIG0_REG, ICM42627_GYRO_CONFIG) < 0) {
     TRACE("ICM42627: failed to write GYRO_CONFIG0");
@@ -145,25 +160,23 @@ static int gyro42627Init(etx_i2c_bus_t bus, uint16_t addr)
   }
   delay_ms(CONFIG_DELAY_MS);
 
-  if (write_cmd(ICM42627_BANK_SEL_REG, ICM42627_BANK1) < 0) {
-    TRACE("ICM42627: failed to select register bank 1");
+  // Power on gyro and accel in Low Noise mode last, now that the signal
+  // path is fully configured. The datasheet requires no register writes
+  // for 200us after an OFF -> mode transition, and the gyro must be kept
+  // on for at least 45ms before its output is valid.
+  if (write_cmd(ICM42627_PWR_MGMT0_REG, ICM42627_PWR_STAGE1) < 0) {
+    TRACE("ICM42627: failed to write PWR_MGMT0 stage 1");
     return -1;
   }
-  delay_ms(CONFIG_DELAY_MS);
+  delay_us(POWER_ON_SETTLE_US);
 
-  if (write_cmd(ICM42627_GYRO_STATIC2_REG, ICM42627_GYRO_STATIC2) < 0) {
-    TRACE("ICM42627: failed to write GYRO_STATIC2");
+  if (write_cmd(ICM42627_PWR_MGMT0_REG, ICM42627_PWR_STAGE2) < 0) {
+    TRACE("ICM42627: failed to write PWR_MGMT0 stage 2");
     return -1;
   }
-  delay_ms(CONFIG_DELAY_MS);
+  delay_ms(GYRO_STARTUP_DELAY_MS);
 
-  if (write_cmd(ICM42627_BANK_SEL_REG, ICM42627_BANK0) < 0) {
-    TRACE("ICM42627: failed to restore register bank 0");
-    return -1;
-  }
-  delay_ms(CONFIG_DELAY_MS);
-
-  // Re-read WHO_AM_I after reset and banked configuration to catch a device
+  // Re-read WHO_AM_I after reset and configuration to catch a device
   // that stopped responding even though the initial probe succeeded.
   if (read_cmd(ICM42627_WHO_AM_I_REG, &who_am_i) < 0 ||
       who_am_i != ICM42627_WHO_AM_I) {

radio/src/drivers/icm42627.h

@@ -23,6 +23,8 @@
 
 #include "hal/imu.h"
 
+#define ICM42627_I2C_BASE_ADDR      0x68
+
 #define ICM42627_WHO_AM_I_REG       0x75
 #define ICM42627_WHO_AM_I           0x20
 

radio/src/targets/horus/CMakeLists.txt

@@ -116,6 +116,8 @@ if (PCB STREQUAL X10)
     set(AUX2_SERIAL OFF)
     set(CSD203_SENSOR ON)
     set(FLYSKY_GIMBAL ON)
+    add_definitions(-DIMU_ICM42627)
+    add_definitions(-DIMU_SC7U22)
     if (BLUETOOTH)
       set(AUX_SERIAL OFF)
     endif()
@@ -285,6 +287,7 @@ add_library(board OBJECT EXCLUDE_FROM_ALL
   targets/common/arm/stm32/heartbeat_driver.cpp
   drivers/lsm6ds.cpp
   drivers/icm42627.cpp
+  drivers/sc7u22.cpp
   targets/common/arm/stm32/mixer_scheduler_driver.cpp
   targets/common/arm/stm32/module_timer_driver.cpp
   targets/common/arm/stm32/sticks_pwm_driver.cpp

radio/src/targets/horus/board.cpp

@@ -52,8 +52,22 @@
   #include "csd203_sensor.h"
 #endif
 
-#if defined(IMU) && defined(IMU_I2C_BUS) && defined(IMU_I2C_ADDRESS)
+#if defined(IMU) && defined(IMU_I2C_BUS) && \
+    (defined(IMU_I2C_ADDRESS) || defined(IMU_ICM42627) || \
+     defined(IMU_SC7U22) || defined(IMU_LSM6DS33))
   #define HAS_IMU
+  #include "gyro.h"
+  #include "stm32_i2c_driver.h"
+  #if defined(IMU_ICM42627)
+  #include "drivers/icm42627.h"
+  #endif
+  #if defined(IMU_SC7U22)
+  #include "drivers/sc7u22.h"
+  #endif
+  #if defined(IMU_LSM6DS33) || \
+      (!defined(IMU_ICM42627) && !defined(IMU_SC7U22) && defined(IMU_I2C_ADDRESS))
+  #include "drivers/lsm6ds.h"
+  #endif
 #endif
 
 HardwareOptions hardwareOptions;
@@ -133,25 +147,26 @@ void audioInit()
 #endif
 
 #if defined(HAS_IMU)
-#include "gyro.h"
-#include "stm32_i2c_driver.h"
-#include "drivers/icm42627.h"
-#include "drivers/lsm6ds.h"
+static const etx_imu_t _imu_candidates[] = {
+#if defined(IMU_ICM42627)
+  { &imu_icm42627_driver, IMU_I2C_BUS, ICM42627_I2C_BASE_ADDR },
+  { &imu_icm42627_driver, IMU_I2C_BUS, ICM42627_I2C_BASE_ADDR + 1 },
+#endif
+#if defined(IMU_SC7U22)
+  { &imu_sc7u22_driver, IMU_I2C_BUS, SC7U22_I2C_BASE_ADDR },
+  { &imu_sc7u22_driver, IMU_I2C_BUS, SC7U22_I2C_BASE_ADDR + 1 },
+#endif
+#if defined(IMU_LSM6DS33) || \
+    (!defined(IMU_ICM42627) && !defined(IMU_SC7U22) && defined(IMU_I2C_ADDRESS))
+  { &imu_lsm6ds_driver, IMU_I2C_BUS, IMU_I2C_ADDRESS },
+#endif
+};
 
 static void gyroInit()
 {
-#if defined(RADIO_V16)
-  const etx_imu_driver_t *driver = &imu_icm42627_driver;
-#else
-  const etx_imu_driver_t *driver = &imu_lsm6ds_driver;
-#endif
-
-  const etx_imu_t candidates[] = {
-    { driver, IMU_I2C_BUS, IMU_I2C_ADDRESS },
-  };
-
-  gyroStart(imuDetect(candidates, DIM(candidates)));
+  gyroStart(imuDetect(_imu_candidates, DIM(_imu_candidates)));
 }
+
 #endif
 
 void boardInit()

radio/src/targets/horus/hal.h

@@ -466,7 +466,6 @@
    #define IMU_I2C_ADDRESS               0x6A
  #elif defined(RADIO_V16)
    #define IMU_I2C_BUS                   I2C_Bus_1
-   #define IMU_I2C_ADDRESS               0x69
  #elif !defined(AUX_SERIAL) && defined(IMU_LSM6DS33)
    #define IMU_I2C_BUS                   I2C_Bus_2
    #define IMU_I2C_ADDRESS               0x6A