diff --git a/libraries/AP_HAL_ChibiOS/AP_HAL_ChibiOS_Namespace.h b/libraries/AP_HAL_ChibiOS/AP_HAL_ChibiOS_Namespace.h
index a7a7aa4c01..09a04a9c6a 100644
--- a/libraries/AP_HAL_ChibiOS/AP_HAL_ChibiOS_Namespace.h
+++ b/libraries/AP_HAL_ChibiOS/AP_HAL_ChibiOS_Namespace.h
@@ -5,6 +5,7 @@ namespace ChibiOS {
     class AnalogSource;
     class DigitalSource;
     class GPIO;
+    class I2CBus;
     class I2CDevice;
     class I2CDeviceManager;
     class OpticalFlow;
@@ -13,6 +14,8 @@ namespace ChibiOS {
     class RCOutput;
     class Scheduler;
     class Semaphore;
+    class SPIBus;
+    class SPIDesc;
     class SPIDevice;
     class SPIDeviceDriver;
     class SPIDeviceManager;
diff --git a/libraries/AP_HAL_ChibiOS/HAL_ChibiOS_Class.cpp b/libraries/AP_HAL_ChibiOS/HAL_ChibiOS_Class.cpp
index 7e73e07f49..751abd029e 100644
--- a/libraries/AP_HAL_ChibiOS/HAL_ChibiOS_Class.cpp
+++ b/libraries/AP_HAL_ChibiOS/HAL_ChibiOS_Class.cpp
@@ -32,8 +32,19 @@ static HAL_UARTC_DRIVER;
 static HAL_UARTD_DRIVER;
 static HAL_UARTE_DRIVER;
 static HAL_UARTF_DRIVER;
+
+#if HAL_USE_I2C == TRUE
 static ChibiOS::I2CDeviceManager i2cDeviceManager;
+#else
+static Empty::I2CDeviceManager i2cDeviceManager;
+#endif
+
+#if HAL_USE_SPI == TRUE
 static ChibiOS::SPIDeviceManager spiDeviceManager;
+#else
+static Empty::SPIDeviceManager spiDeviceManager;
+#endif
+
 static ChibiOS::AnalogIn analogIn;
 #ifdef HAL_USE_EMPTY_STORAGE
 static Empty::Storage storageDriver;
@@ -42,7 +53,13 @@ static ChibiOS::Storage storageDriver;
 #endif
 static ChibiOS::GPIO gpioDriver;
 static ChibiOS::RCInput rcinDriver;
+
+#if HAL_USE_PWM == TRUE
 static ChibiOS::RCOutput rcoutDriver;
+#else
+static Empty::RCOutput rcoutDriver;
+#endif
+
 static ChibiOS::Scheduler schedulerInstance;
 static ChibiOS::Util utilInstance;
 static Empty::OpticalFlow opticalFlowDriver;
@@ -168,6 +185,8 @@ void HAL_ChibiOS::run(int argc, char * const argv[], Callbacks* callbacks) const
      * - Kernel initialization, the main() function becomes a thread and the
      *   RTOS is active.
      */
+
+#ifdef HAL_STDOUT_SERIAL
     //STDOUT Initialistion
     SerialConfig stdoutcfg =
     {
@@ -177,6 +196,7 @@ void HAL_ChibiOS::run(int argc, char * const argv[], Callbacks* callbacks) const
       0
     };
     sdStart((SerialDriver*)&HAL_STDOUT_SERIAL, &stdoutcfg);
+#endif
 
     //Setup SD Card and Initialise FATFS bindings
     /*
diff --git a/libraries/AP_HAL_ChibiOS/I2CDevice.cpp b/libraries/AP_HAL_ChibiOS/I2CDevice.cpp
index b063d1d6fa..b12d628dd5 100644
--- a/libraries/AP_HAL_ChibiOS/I2CDevice.cpp
+++ b/libraries/AP_HAL_ChibiOS/I2CDevice.cpp
@@ -22,6 +22,8 @@
 #include "ch.h"
 #include "hal.h"
 
+#if HAL_USE_I2C == TRUE
+
 static const struct I2CInfo {
     struct I2CDriver *i2c;
     uint8_t dma_channel_rx;
@@ -283,3 +285,5 @@ I2CDeviceManager::get_device(uint8_t bus, uint8_t address,
     auto dev = AP_HAL::OwnPtr<AP_HAL::I2CDevice>(new I2CDevice(bus, address, bus_clock, use_smbus, timeout_ms));
     return dev;
 }
+
+#endif // HAL_USE_I2C
diff --git a/libraries/AP_HAL_ChibiOS/I2CDevice.h b/libraries/AP_HAL_ChibiOS/I2CDevice.h
index 661e17ffea..51c5e172f1 100644
--- a/libraries/AP_HAL_ChibiOS/I2CDevice.h
+++ b/libraries/AP_HAL_ChibiOS/I2CDevice.h
@@ -28,9 +28,11 @@
 #include "Device.h"
 #include "shared_dma.h"
 
-namespace ChibiOS {
+#if HAL_USE_I2C == TRUE
 
-class I2CBus : public DeviceBus {
+using namespace ChibiOS;
+
+class ChibiOS::I2CBus : public ChibiOS::DeviceBus {
 public:
     I2CConfig i2ccfg;
     uint8_t busnum;
@@ -44,7 +46,7 @@ public:
     static void clear_bus(ioline_t scl_line, uint8_t scl_af);
 };
     
-class I2CDevice : public AP_HAL::I2CDevice {
+class ChibiOS::I2CDevice : public AP_HAL::I2CDevice {
 public:
     static I2CDevice *from(AP_HAL::I2CDevice *dev)
     {
@@ -100,7 +102,7 @@ private:
     uint32_t _timeout_ms;
 };
 
-class I2CDeviceManager : public AP_HAL::I2CDeviceManager {
+class ChibiOS::I2CDeviceManager : public AP_HAL::I2CDeviceManager {
 public:
     friend class I2CDevice;
 
@@ -120,4 +122,5 @@ public:
                                                  uint32_t timeout_ms=4) override;
 };
 
-}
+#endif // HAL_USE_I2C
+
diff --git a/libraries/AP_HAL_ChibiOS/RCOutput.cpp b/libraries/AP_HAL_ChibiOS/RCOutput.cpp
index d57b640f36..3934aeec77 100644
--- a/libraries/AP_HAL_ChibiOS/RCOutput.cpp
+++ b/libraries/AP_HAL_ChibiOS/RCOutput.cpp
@@ -18,6 +18,8 @@
 #include <AP_Math/AP_Math.h>
 #include <AP_BoardConfig/AP_BoardConfig.h>
 
+#if HAL_USE_PWM == TRUE
+
 using namespace ChibiOS;
 
 extern const AP_HAL::HAL& hal;
@@ -494,3 +496,5 @@ void RCOutput::timer_tick(void)
         trigger_oneshot();
     }
 }
+
+#endif // HAL_USE_PWM
diff --git a/libraries/AP_HAL_ChibiOS/RCOutput.h b/libraries/AP_HAL_ChibiOS/RCOutput.h
index 393de41c34..5231c7b42b 100644
--- a/libraries/AP_HAL_ChibiOS/RCOutput.h
+++ b/libraries/AP_HAL_ChibiOS/RCOutput.h
@@ -20,6 +20,8 @@
 #include "ch.h"
 #include "hal.h"
 
+#if HAL_USE_PWM == TRUE
+
 class ChibiOS::RCOutput : public AP_HAL::RCOutput {
 public:
     void     init();
@@ -116,3 +118,5 @@ private:
     // trigger oneshot pulses
     void trigger_oneshot(void);
 };
+
+#endif // HAL_USE_PWM
diff --git a/libraries/AP_HAL_ChibiOS/SPIDevice.cpp b/libraries/AP_HAL_ChibiOS/SPIDevice.cpp
index 186230d3f7..198dff8b4d 100644
--- a/libraries/AP_HAL_ChibiOS/SPIDevice.cpp
+++ b/libraries/AP_HAL_ChibiOS/SPIDevice.cpp
@@ -21,6 +21,8 @@
 #include "Semaphores.h"
 #include <stdio.h>
 
+#if HAL_USE_SPI == TRUE
+
 using namespace ChibiOS;
 extern const AP_HAL::HAL& hal;
 
@@ -45,7 +47,7 @@ static const struct SPIDriverInfo {
 #define MHZ (1000U*1000U)
 #define KHZ (1000U)
 // device list comes from hwdef.dat
-SPIDesc SPIDeviceManager::device_table[] = { HAL_SPI_DEVICE_LIST };
+ChibiOS::SPIDesc SPIDeviceManager::device_table[] = { HAL_SPI_DEVICE_LIST };
 
 SPIBus::SPIBus(uint8_t _bus) :
     DeviceBus(APM_SPI_PRIORITY),
@@ -323,3 +325,5 @@ SPIDeviceManager::get_device(const char *name)
 
     return AP_HAL::OwnPtr<AP_HAL::SPIDevice>(new SPIDevice(*busp, desc));
 }
+
+#endif
diff --git a/libraries/AP_HAL_ChibiOS/SPIDevice.h b/libraries/AP_HAL_ChibiOS/SPIDevice.h
index 6486695bca..89703a3908 100644
--- a/libraries/AP_HAL_ChibiOS/SPIDevice.h
+++ b/libraries/AP_HAL_ChibiOS/SPIDevice.h
@@ -21,11 +21,11 @@
 #include "Scheduler.h"
 #include "Device.h"
 
-namespace ChibiOS {
+#if HAL_USE_SPI == TRUE
 
-class SPIDesc;
+using namespace ChibiOS;
 
-class SPIBus : public DeviceBus {
+class ChibiOS::SPIBus : public ChibiOS::DeviceBus {
 public:
     SPIBus(uint8_t bus);
     struct spi_dev_s *dev;
@@ -36,7 +36,7 @@ public:
     bool spi_started;
 };
 
-struct SPIDesc {
+struct ChibiOS::SPIDesc {
     SPIDesc(const char *_name, uint8_t _bus,
             uint8_t _device, ioline_t _pal_line,
             uint16_t _mode, uint32_t _lowspeed, uint32_t _highspeed)
@@ -56,7 +56,7 @@ struct SPIDesc {
 };
 
 
-class SPIDevice : public AP_HAL::SPIDevice {
+class ChibiOS::SPIDevice : public AP_HAL::SPIDevice {
 public:
     SPIDevice(SPIBus &_bus, SPIDesc &_device_desc);
 
@@ -101,7 +101,7 @@ private:
     uint16_t derive_freq_flag(uint32_t _frequency);
 };
 
-class SPIDeviceManager : public AP_HAL::SPIDeviceManager {
+class ChibiOS::SPIDeviceManager : public AP_HAL::SPIDeviceManager {
 public:
     friend class SPIDevice;
 
@@ -117,4 +117,5 @@ private:
     SPIBus *buses;
 };
 
-}
+
+#endif // HAL_USE_SPI
diff --git a/libraries/AP_HAL_ChibiOS/Storage.cpp b/libraries/AP_HAL_ChibiOS/Storage.cpp
index 7dbf348f3a..f1a9d24a28 100644
--- a/libraries/AP_HAL_ChibiOS/Storage.cpp
+++ b/libraries/AP_HAL_ChibiOS/Storage.cpp
@@ -15,8 +15,6 @@
  * Code by Andrew Tridgell and Siddharth Bharat Purohit
  */
 #include <AP_HAL/AP_HAL.h>
-#if CONFIG_HAL_BOARD == HAL_BOARD_CHIBIOS
-
 #include <AP_BoardConfig/AP_BoardConfig.h>
 
 #include "Storage.h"
@@ -24,6 +22,7 @@
 
 using namespace ChibiOS;
 
+#ifndef HAL_USE_EMPTY_STORAGE
 
 extern const AP_HAL::HAL& hal;
 
@@ -198,4 +197,4 @@ bool Storage::_flash_erase_ok(void)
     return !hal.util->get_soft_armed();
 }
 
-#endif // CONFIG_HAL_BOARD
+#endif // HAL_USE_EMPTY_STORAGE
diff --git a/libraries/AP_HAL_ChibiOS/Storage.h b/libraries/AP_HAL_ChibiOS/Storage.h
index f8f4a57ce6..fea40c2a2a 100644
--- a/libraries/AP_HAL_ChibiOS/Storage.h
+++ b/libraries/AP_HAL_ChibiOS/Storage.h
@@ -25,6 +25,8 @@
 
 #define CH_STORAGE_SIZE HAL_STORAGE_SIZE
 
+#ifndef HAL_USE_EMPTY_STORAGE
+
 // when using flash storage we use a small line size to make storage
 // compact and minimise the number of erase cycles needed
 #define CH_STORAGE_LINE_SHIFT 3
@@ -71,3 +73,5 @@ private:
     bool using_fram;
 #endif
 };
+
+#endif // HAL_USE_EMPTY_STORAGE
diff --git a/libraries/AP_HAL_ChibiOS/ToneAlarm.h b/libraries/AP_HAL_ChibiOS/ToneAlarm.h
index 4fc3d33e89..ee28b5e9c7 100644
--- a/libraries/AP_HAL_ChibiOS/ToneAlarm.h
+++ b/libraries/AP_HAL_ChibiOS/ToneAlarm.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include "AP_HAL_ChibiOS.h"
+
 #include "ch.h"
 #include "hal.h"
 
@@ -110,6 +111,8 @@
 
 #define TONE_NUMBER_OF_TUNES 11
 
+#ifdef HAL_PWM_ALARM
+
 namespace ChibiOS {
 
 class ToneAlarm {
@@ -149,3 +152,4 @@ private:
 };
 
 }
+#endif // HAL_PWM_ALARM
diff --git a/libraries/AP_HAL_ChibiOS/UARTDriver.cpp b/libraries/AP_HAL_ChibiOS/UARTDriver.cpp
index 31f103dfbd..7325b5c4cd 100644
--- a/libraries/AP_HAL_ChibiOS/UARTDriver.cpp
+++ b/libraries/AP_HAL_ChibiOS/UARTDriver.cpp
@@ -186,6 +186,7 @@ void UARTDriver::begin(uint32_t b, uint16_t rxS, uint16_t txS)
         }
 #endif
     } else {
+#if HAL_USE_SERIAL == TRUE
         if (_baudrate != 0) {
             bool was_initialised = _device_initialised;            
             //setup Rx DMA
@@ -248,6 +249,7 @@ void UARTDriver::begin(uint32_t b, uint16_t rxS, uint16_t txS)
                 }
             }
         }
+#endif // HAL_USE_SERIAL
     }
 
     if (_writebuf.get_size() && _readbuf.get_size()) {
@@ -261,6 +263,7 @@ void UARTDriver::begin(uint32_t b, uint16_t rxS, uint16_t txS)
 
 void UARTDriver::dma_tx_allocate(void)
 {
+#if HAL_USE_SERIAL == TRUE
     osalDbgAssert(txdma == nullptr, "double DMA allocation");
     txdma = STM32_DMA_STREAM(sdef.dma_tx_stream_id);
     chSysLock();
@@ -271,6 +274,7 @@ void UARTDriver::dma_tx_allocate(void)
     osalDbgAssert(!dma_allocated, "stream already allocated");
     chSysUnlock();
     dmaStreamSetPeripheral(txdma, &((SerialDriver*)sdef.serial)->usart->DR);
+#endif // HAL_USE_SERIAL
 }
 
 void UARTDriver::dma_tx_deallocate(void)
@@ -303,6 +307,7 @@ void UARTDriver::tx_complete(void* self, uint32_t flags)
 
 void UARTDriver::rx_irq_cb(void* self)
 {
+#if HAL_USE_SERIAL == TRUE
     UARTDriver* uart_drv = (UARTDriver*)self;
     if (!uart_drv->sdef.dma_rx) {
         return;
@@ -314,10 +319,12 @@ void UARTDriver::rx_irq_cb(void* self)
         //disable dma, triggering DMA transfer complete interrupt
         uart_drv->rxdma->stream->CR &= ~STM32_DMA_CR_EN;
     }
+#endif // HAL_USE_SERIAL
 }
 
 void UARTDriver::rxbuff_full_irq(void* self, uint32_t flags)
 {
+#if HAL_USE_SERIAL == TRUE
     UARTDriver* uart_drv = (UARTDriver*)self;
     if (uart_drv->_lock_rx_in_timer_tick) {
         return;
@@ -342,6 +349,7 @@ void UARTDriver::rxbuff_full_irq(void* self, uint32_t flags)
     if (uart_drv->_rts_is_active) {
         uart_drv->update_rts_line();
     }
+#endif // HAL_USE_SERIAL
 }
 
 void UARTDriver::begin(uint32_t b)
@@ -360,7 +368,9 @@ void UARTDriver::end()
         sduStop((SerialUSBDriver*)sdef.serial);
 #endif
     } else {
+#if HAL_USE_SERIAL == TRUE
         sdStop((SerialDriver*)sdef.serial);
+#endif
     }
     _readbuf.set_size(0);
     _writebuf.set_size(0);
@@ -558,14 +568,16 @@ void UARTDriver::write_pending_bytes_NODMA(uint32_t n)
     ByteBuffer::IoVec vec[2];
     const auto n_vec = _writebuf.peekiovec(vec, n);
     for (int i = 0; i < n_vec; i++) {
-        int ret;
+        int ret = -1;
         if (sdef.is_usb) {
             ret = 0;
 #ifdef HAVE_USB_SERIAL
             ret = chnWriteTimeout((SerialUSBDriver*)sdef.serial, vec[i].data, vec[i].len, TIME_IMMEDIATE);
 #endif
         } else {
+#if HAL_USE_SERIAL == TRUE
             ret = chnWriteTimeout((SerialDriver*)sdef.serial, vec[i].data, vec[i].len, TIME_IMMEDIATE);
+#endif
         }
         if (ret < 0) {
             break;
@@ -682,7 +694,9 @@ void UARTDriver::_timer_tick(void)
     #endif
             } else {
                 ret = 0;
+#if HAL_USE_SERIAL == TRUE
                 ret = chnReadTimeout((SerialDriver*)sdef.serial, vec[i].data, vec[i].len, TIME_IMMEDIATE);
+#endif
             }
             if (ret < 0) {
                 break;
@@ -721,7 +735,7 @@ void UARTDriver::set_flow_control(enum flow_control flowcontrol)
         // no hw flow control available
         return;
     }
-
+#if HAL_USE_SERIAL == TRUE
     _flow_control = flowcontrol;
     if (!_initialised) {
         // not ready yet, we just set variable for when we call begin
@@ -755,6 +769,7 @@ void UARTDriver::set_flow_control(enum flow_control flowcontrol)
         ((SerialDriver*)(sdef.serial))->usart->CR3 &= ~USART_CR3_RTSE;
         break;
     }
+#endif // HAL_USE_SERIAL
 }
 
 /*
@@ -798,6 +813,7 @@ void UARTDriver::configure_parity(uint8_t v)
         // not possible
         return;
     }
+#if HAL_USE_SERIAL == TRUE
     // stop and start to take effect
     sdStop((SerialDriver*)sdef.serial);
     
@@ -826,6 +842,7 @@ void UARTDriver::configure_parity(uint8_t v)
         //because we will handle them via DMA
         ((SerialDriver*)sdef.serial)->usart->CR1 &= ~USART_CR1_RXNEIE;
     }
+#endif // HAL_USE_SERIAL
 }
 
 /*
@@ -837,6 +854,7 @@ void UARTDriver::set_stop_bits(int n)
         // not possible
         return;
     }
+#if HAL_USE_SERIAL
     // stop and start to take effect
     sdStop((SerialDriver*)sdef.serial);
     
@@ -854,6 +872,7 @@ void UARTDriver::set_stop_bits(int n)
         //because we will handle them via DMA
         ((SerialDriver*)sdef.serial)->usart->CR1 &= ~USART_CR1_RXNEIE;
     }
+#endif // HAL_USE_SERIAL
 }
 
 
diff --git a/libraries/AP_HAL_ChibiOS/UARTDriver.h b/libraries/AP_HAL_ChibiOS/UARTDriver.h
index ebcbbe8ffe..650dff277e 100644
--- a/libraries/AP_HAL_ChibiOS/UARTDriver.h
+++ b/libraries/AP_HAL_ChibiOS/UARTDriver.h
@@ -90,7 +90,9 @@ private:
     
     uint32_t _baudrate;
     uint16_t tx_len;
+#if HAL_USE_SERIAL == TRUE
     SerialConfig sercfg;
+#endif
     const thread_t* _uart_owner_thd;
 
     struct {
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/common/stdio.c b/libraries/AP_HAL_ChibiOS/hwdef/common/stdio.c
index 65528353a6..d47945c06c 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/common/stdio.c
+++ b/libraries/AP_HAL_ChibiOS/hwdef/common/stdio.c
@@ -99,7 +99,12 @@ int asprintf(char **strp, const char *fmt, ...)
 
 int vprintf(const char *fmt, va_list arg)
 {
+#ifdef HAL_STDOUT_SERIAL
   return chvprintf ((BaseSequentialStream*)&HAL_STDOUT_SERIAL, fmt, arg);
+#else
+  (void)arg;
+  return strlen(fmt);
+#endif
 }
 
 int printf(const char *fmt, ...)
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/scripts/chibios_hwdef.py b/libraries/AP_HAL_ChibiOS/hwdef/scripts/chibios_hwdef.py
index 88ee2a3900..d26295cff3 100755
--- a/libraries/AP_HAL_ChibiOS/hwdef/scripts/chibios_hwdef.py
+++ b/libraries/AP_HAL_ChibiOS/hwdef/scripts/chibios_hwdef.py
@@ -100,6 +100,12 @@ def get_alt_function(mcu, pin, function):
             return alt_map[s]
     return None
 
+def have_type_prefix(ptype):
+    '''return True if we have a peripheral starting with the given peripheral type'''
+    for t in bytype.keys():
+        if t.startswith(ptype):
+            return True
+    return False
 
 def get_ADC1_chan(mcu, pin):
     '''return ADC1 channel for an analog pin'''
@@ -290,10 +296,10 @@ def write_mcu_config(f):
     f.write('// crystal frequency\n')
     f.write('#define STM32_HSECLK %sU\n\n' % get_config('OSCILLATOR_HZ'))
     f.write('// UART used for stdout (printf)\n')
-    f.write('#define HAL_STDOUT_SERIAL %s\n\n' % get_config('STDOUT_SERIAL'))
-    f.write('// baudrate used for stdout (printf)\n')
-    f.write('#define HAL_STDOUT_BAUDRATE %u\n\n' % get_config(
-        'STDOUT_BAUDRATE', type=int))
+    if get_config('STDOUT_SERIAL', required=False):
+        f.write('#define HAL_STDOUT_SERIAL %s\n\n' % get_config('STDOUT_SERIAL'))
+        f.write('// baudrate used for stdout (printf)\n')
+        f.write('#define HAL_STDOUT_BAUDRATE %u\n\n' % get_config('STDOUT_BAUDRATE', type=int))
     if 'SDIO' in bytype:
         f.write('// SDIO available, enable POSIX filesystem support\n')
         f.write('#define USE_POSIX\n\n')
@@ -308,7 +314,7 @@ def write_mcu_config(f):
         f.write('#define HAL_USE_SERIAL_USB TRUE\n')
     if 'OTG2' in bytype:
         f.write('#define STM32_USB_USE_OTG2                  TRUE\n')
-    if 'CAN1' in bytype or 'CAN2' in bytype or 'CAN3' in bytype:
+    if have_type_prefix('CAN'):
         enable_can(f)
     # write any custom STM32 defines
     for d in alllines:
@@ -362,7 +368,7 @@ INCLUDE common.ld
 
 def write_USB_config(f):
     '''write USB config defines'''
-    if not 'OTG1' in bytype:
+    if not have_type_prefix('OTG'):
         return;
     f.write('// USB configuration\n')
     f.write('#define HAL_USB_VENDOR_ID %s\n' % get_config('USB_VENDOR', default=0x0483)) # default to ST
@@ -505,13 +511,16 @@ def write_UART_config(f):
 
 def write_I2C_config(f):
     '''write I2C config defines'''
+    if not have_type_prefix('I2C'):
+        print("No I2C peripherals")
+        f.write('#define HAL_USE_I2C FALSE\n')
+        return
     if not 'I2C_ORDER' in config:
         error("Missing I2C_ORDER config")
     i2c_list = config['I2C_ORDER']
     f.write('// I2C configuration\n')
     if len(i2c_list) == 0:
-        f.write('#define HAL_USE_I2C FALSE\n')
-        return
+        error("I2C_ORDER invalid")
     devlist = []
     for dev in i2c_list:
         if not dev.startswith('I2C') or dev[3] not in "1234":
@@ -547,6 +556,11 @@ def write_PWM_config(f):
                     pwm_out.append(p)
                 if p.type not in pwm_timers:
                     pwm_timers.append(p.type)
+
+    if not pwm_out:
+        print("No PWM output defined")
+        f.write('#define HAL_USE_PWM FALSE\n')
+        
     if rc_in is not None:
         a = rc_in.label.split('_')
         chan_str = a[1][2:]