diff --git a/libraries/AP_HAL_ChibiOS/I2CDevice.cpp b/libraries/AP_HAL_ChibiOS/I2CDevice.cpp
index 0549a19d3c..839634e3a4 100644
--- a/libraries/AP_HAL_ChibiOS/I2CDevice.cpp
+++ b/libraries/AP_HAL_ChibiOS/I2CDevice.cpp
@@ -118,7 +118,7 @@ I2CDeviceManager::I2CDeviceManager(void)
           drop the speed to be the minimum speed requested
          */
         businfo[i].busclock = HAL_I2C_MAX_CLOCK;
-#if defined(STM32F7)
+#if defined(STM32F7) || defined(STM32H7)
         if (businfo[i].busclock <= 100000) {
             businfo[i].i2ccfg.timingr = HAL_I2C_F7_100_TIMINGR;
             businfo[i].busclock = 100000;
@@ -150,7 +150,7 @@ I2CDevice::I2CDevice(uint8_t busnum, uint8_t address, uint32_t bus_clock, bool u
     asprintf(&pname, "I2C:%u:%02x",
              (unsigned)busnum, (unsigned)address);
     if (bus_clock < bus.busclock) {
-#if defined(STM32F7)
+#if defined(STM32F7) || defined(STM32H7)
         if (bus_clock <= 100000) {
             bus.i2ccfg.timingr = HAL_I2C_F7_100_TIMINGR;
             bus.busclock = 100000;
@@ -197,7 +197,7 @@ bool I2CDevice::transfer(const uint8_t *send, uint32_t send_len,
         return false;
     }
     
-#if defined(STM32F7)
+#if defined(STM32F7) || defined(STM32H7)
     if (_use_smbus) {
         bus.i2ccfg.cr1 |= I2C_CR1_SMBHEN;
     } else {
diff --git a/libraries/AP_HAL_ChibiOS/SPIDevice.cpp b/libraries/AP_HAL_ChibiOS/SPIDevice.cpp
index e40faa623d..7b79338274 100644
--- a/libraries/AP_HAL_ChibiOS/SPIDevice.cpp
+++ b/libraries/AP_HAL_ChibiOS/SPIDevice.cpp
@@ -29,10 +29,17 @@ using namespace ChibiOS;
 extern const AP_HAL::HAL& hal;
 
 // SPI mode numbers
+#if defined(STM32H7)
+#define SPIDEV_MODE0    0
+#define SPIDEV_MODE1    SPI_CFG2_CPHA
+#define SPIDEV_MODE2    SPI_CFG2_CPOL
+#define SPIDEV_MODE3    SPI_CFG2_CPOL | SPI_CFG2_CPHA
+#else
 #define SPIDEV_MODE0    0
 #define SPIDEV_MODE1    SPI_CR1_CPHA
 #define SPIDEV_MODE2    SPI_CR1_CPOL
 #define SPIDEV_MODE3    SPI_CR1_CPOL | SPI_CR1_CPHA
+#endif
 
 #define SPI1_CLOCK  STM32_PCLK2
 #define SPI2_CLOCK  STM32_PCLK1
@@ -190,7 +197,7 @@ bool SPIDevice::clock_pulse(uint32_t n)
     return true;
 }
 
-uint16_t SPIDevice::derive_freq_flag_bus(uint8_t busid, uint32_t _frequency)
+uint32_t SPIDevice::derive_freq_flag_bus(uint8_t busid, uint32_t _frequency)
 {
     uint32_t spi_clock_freq = SPI1_CLOCK;
     if (busid > 0 && uint8_t(busid-1) < ARRAY_SIZE(bus_clocks)) {
@@ -207,10 +214,14 @@ uint16_t SPIDevice::derive_freq_flag_bus(uint8_t busid, uint32_t _frequency)
     // assuming the bitrate bits are consecutive in the CR1 register,
     // we can just multiply by BR_0 to get the right bits for the desired
     // scaling
+#if defined(STM32H7)
+    return (i * SPI_CFG1_MBR_0) | SPI_CFG1_DSIZE_VALUE(7); // 8 bit transfers
+#else
     return i * SPI_CR1_BR_0;
+#endif
 }
 
-uint16_t SPIDevice::derive_freq_flag(uint32_t _frequency)
+uint32_t SPIDevice::derive_freq_flag(uint32_t _frequency)
 {
     uint8_t busid = spi_devices[device_desc.bus].busid;
     return derive_freq_flag_bus(busid, _frequency);
@@ -293,8 +304,13 @@ bool SPIDevice::acquire_bus(bool set, bool skip_cs)
         bus.spicfg.end_cb = nullptr;
         bus.spicfg.ssport = PAL_PORT(device_desc.pal_line);
         bus.spicfg.sspad = PAL_PAD(device_desc.pal_line);
+#if defined(STM32H7)
+        bus.spicfg.cfg1 = freq_flag;
+        bus.spicfg.cfg2 = device_desc.mode;
+#else
         bus.spicfg.cr1 = (uint16_t)(freq_flag | device_desc.mode);
         bus.spicfg.cr2 = 0;
+#endif
         if (bus.spi_started) {
             spiStop(spi_devices[device_desc.bus].driver);
             bus.spi_started = false;
@@ -379,7 +395,11 @@ void SPIDevice::test_clock_freq(void)
         SPIConfig spicfg {};
         const uint32_t target_freq = 2000000UL;
         // use a clock divisor of 256 for maximum resolution
+#if defined(STM32H7)
+        spicfg.cfg1 = derive_freq_flag_bus(spi_devices[i].busid, target_freq);
+#else
         spicfg.cr1 = derive_freq_flag_bus(spi_devices[i].busid, target_freq);
+#endif
         spiAcquireBus(spi_devices[i].driver);
         spiStart(spi_devices[i].driver, &spicfg);
         uint32_t t0 = AP_HAL::micros();
diff --git a/libraries/AP_HAL_ChibiOS/SPIDevice.h b/libraries/AP_HAL_ChibiOS/SPIDevice.h
index ea478d8eb1..59f02021cc 100644
--- a/libraries/AP_HAL_ChibiOS/SPIDevice.h
+++ b/libraries/AP_HAL_ChibiOS/SPIDevice.h
@@ -48,7 +48,7 @@ public:
 struct SPIDesc {
     SPIDesc(const char *_name, uint8_t _bus,
             uint8_t _device, ioline_t _pal_line,
-            uint16_t _mode, uint32_t _lowspeed, uint32_t _highspeed)
+            uint32_t _mode, uint32_t _lowspeed, uint32_t _highspeed)
         : name(_name), bus(_bus), device(_device),
           pal_line(_pal_line), mode(_mode),
           lowspeed(_lowspeed), highspeed(_highspeed)
@@ -59,7 +59,7 @@ struct SPIDesc {
     uint8_t bus;
     uint8_t device;
     ioline_t pal_line;
-    uint16_t mode;
+    uint32_t mode;
     uint32_t lowspeed;
     uint32_t highspeed;
 };
@@ -119,14 +119,14 @@ private:
     SPIBus &bus;
     SPIDesc &device_desc;
     uint32_t frequency;
-    uint16_t freq_flag;
-    uint16_t freq_flag_low;
-    uint16_t freq_flag_high;
+    uint32_t freq_flag;
+    uint32_t freq_flag_low;
+    uint32_t freq_flag_high;
     char *pname;
     bool cs_forced;
     static void *spi_thread(void *arg);
-    static uint16_t derive_freq_flag_bus(uint8_t busid, uint32_t _frequency);
-    uint16_t derive_freq_flag(uint32_t _frequency);
+    static uint32_t derive_freq_flag_bus(uint8_t busid, uint32_t _frequency);
+    uint32_t derive_freq_flag(uint32_t _frequency);
 };
 
 class SPIDeviceManager : public AP_HAL::SPIDeviceManager {
diff --git a/libraries/AP_HAL_ChibiOS/UARTDriver.cpp b/libraries/AP_HAL_ChibiOS/UARTDriver.cpp
index 94714cdff9..6fbdcc618b 100644
--- a/libraries/AP_HAL_ChibiOS/UARTDriver.cpp
+++ b/libraries/AP_HAL_ChibiOS/UARTDriver.cpp
@@ -234,7 +234,7 @@ void UARTDriver::begin(uint32_t b, uint16_t rxS, uint16_t txS)
                                             (void *)this);
                     osalDbgAssert(rxdma, "stream alloc failed");
                     chSysUnlock();
-#if defined(STM32F7)
+#if defined(STM32F7) || defined(STM32H7)
                     dmaStreamSetPeripheral(rxdma, &((SerialDriver*)sdef.serial)->usart->RDR);
 #else
                     dmaStreamSetPeripheral(rxdma, &((SerialDriver*)sdef.serial)->usart->DR);
@@ -322,7 +322,7 @@ void UARTDriver::dma_tx_allocate(Shared_DMA *ctx)
                             (void *)this);
     osalDbgAssert(txdma, "stream alloc failed");
     chSysUnlock();
-#if defined(STM32F7)
+#if defined(STM32F7) || defined(STM32H7)
     dmaStreamSetPeripheral(txdma, &((SerialDriver*)sdef.serial)->usart->TDR);
 #else
     dmaStreamSetPeripheral(txdma, &((SerialDriver*)sdef.serial)->usart->DR);
@@ -368,7 +368,7 @@ void UARTDriver::rx_irq_cb(void* self)
     if (!uart_drv->sdef.dma_rx) {
         return;
     }
-#if defined(STM32F7)
+#if defined(STM32F7) || defined(STM32H7)
     //disable dma, triggering DMA transfer complete interrupt
     uart_drv->rxdma->stream->CR &= ~STM32_DMA_CR_EN;
 #else