stm32/can: Allow CAN pins to be configured per board.

This patch allows a given board to configure which pins are used for the
CAN peripherals, in a similar way to all the other bus peripherals (I2C,
UART, SPI).  To enable CAN on a board the mpconfigboard.h file should
define (for example):

    #define MICROPY_HW_CAN1_TX (pin_B9)
    #define MICROPY_HW_CAN1_RX (pin_B8)
    #define MICROPY_HW_CAN2_TX (pin_B13)
    #define MICROPY_HW_CAN2_RX (pin_B12)

And the board config file should no longer define MICROPY_HW_ENABLE_CAN.

ports/stm32/boards/CERB40/mpconfigboard.h

@@ -5,7 +5,6 @@
 #define MICROPY_HW_ENABLE_RNG       (1)
 #define MICROPY_HW_ENABLE_RTC       (1)
 #define MICROPY_HW_ENABLE_DAC       (1)
-#define MICROPY_HW_ENABLE_CAN       (1)
 #define MICROPY_HW_ENABLE_USB       (1)
 
 // HSE is 12MHz
@@ -50,6 +49,12 @@
 #define MICROPY_HW_SPI3_MISO (pin_B4)
 #define MICROPY_HW_SPI3_MOSI (pin_B5)
 
+// CAN busses
+#define MICROPY_HW_CAN1_TX (pin_B9)
+#define MICROPY_HW_CAN1_RX (pin_B8)
+#define MICROPY_HW_CAN2_TX (pin_B13)
+#define MICROPY_HW_CAN2_RX (pin_B12)
+
 // The Cerb40 has No LEDs
 
 // The Cerb40 has No SDCard

ports/stm32/boards/CERB40/pins.csv

@@ -44,3 +44,5 @@ UART3_TX,PD8
 UART3_RX,PD9
 UART3_RTS,PD12
 UART3_CTS,PD11
+CAN2_TX,PB13
+CAN2_RX,PB12

ports/stm32/boards/NUCLEO_F429ZI/mpconfigboard.h

@@ -5,7 +5,6 @@
 #define MICROPY_HW_HAS_FLASH        (1)
 #define MICROPY_HW_ENABLE_RNG       (1)
 #define MICROPY_HW_ENABLE_RTC       (1)
-#define MICROPY_HW_ENABLE_CAN       (1)
 #define MICROPY_HW_ENABLE_USB       (1)
 
 // HSE is 8MHz
@@ -59,6 +58,12 @@
 #define MICROPY_HW_SPI5_MISO    (pin_F8)
 #define MICROPY_HW_SPI5_MOSI    (pin_F9)
 
+// CAN busses
+#define MICROPY_HW_CAN1_TX (pin_B9)
+#define MICROPY_HW_CAN1_RX (pin_B8)
+#define MICROPY_HW_CAN2_TX (pin_B13)
+#define MICROPY_HW_CAN2_RX (pin_B12)
+
 // USRSW is pulled low. Pressing the button makes the input go high.
 #define MICROPY_HW_USRSW_PIN        (pin_C13)
 #define MICROPY_HW_USRSW_PULL       (GPIO_NOPULL)

ports/stm32/boards/NUCLEO_F746ZG/mpconfigboard.h

@@ -11,7 +11,6 @@
 #define MICROPY_HW_ENABLE_RNG       (1)
 #define MICROPY_HW_ENABLE_RTC       (1)
 #define MICROPY_HW_ENABLE_DAC       (1)
-#define MICROPY_HW_ENABLE_CAN       (1)
 #define MICROPY_HW_ENABLE_USB       (1)
 
 // HSE is 8MHz
@@ -53,6 +52,12 @@
 #define MICROPY_HW_SPI3_MISO        (pin_B4)
 #define MICROPY_HW_SPI3_MOSI        (pin_B5)
 
+// CAN busses
+#define MICROPY_HW_CAN1_TX          (pin_B9)
+#define MICROPY_HW_CAN1_RX          (pin_B8)
+#define MICROPY_HW_CAN2_TX          (pin_B13)
+#define MICROPY_HW_CAN2_RX          (pin_B12)
+
 // USRSW is pulled low. Pressing the button makes the input go high.
 #define MICROPY_HW_USRSW_PIN        (pin_C13)
 #define MICROPY_HW_USRSW_PULL       (GPIO_NOPULL)

ports/stm32/boards/NUCLEO_F767ZI/mpconfigboard.h

@@ -11,7 +11,6 @@
 #define MICROPY_HW_ENABLE_RNG       (1)
 #define MICROPY_HW_ENABLE_RTC       (1)
 #define MICROPY_HW_ENABLE_DAC       (1)
-#define MICROPY_HW_ENABLE_CAN       (1)
 #define MICROPY_HW_ENABLE_USB       (1)
 
 // HSE is 25MHz
@@ -53,6 +52,12 @@
 #define MICROPY_HW_SPI3_MISO        (pin_B4)
 #define MICROPY_HW_SPI3_MOSI        (pin_B5)
 
+// CAN busses
+#define MICROPY_HW_CAN1_TX          (pin_B9)
+#define MICROPY_HW_CAN1_RX          (pin_B8)
+#define MICROPY_HW_CAN2_TX          (pin_B13)
+#define MICROPY_HW_CAN2_RX          (pin_B12)
+
 // USRSW is pulled low. Pressing the button makes the input go high.
 #define MICROPY_HW_USRSW_PIN        (pin_C13)
 #define MICROPY_HW_USRSW_PULL       (GPIO_NOPULL)

ports/stm32/boards/OLIMEX_E407/mpconfigboard.h

@@ -7,7 +7,6 @@
 #define MICROPY_HW_ENABLE_RNG       (1)
 #define MICROPY_HW_ENABLE_RTC       (1)
 #define MICROPY_HW_ENABLE_DAC       (1)
-#define MICROPY_HW_ENABLE_CAN       (1)
 #define MICROPY_HW_ENABLE_USB       (1)
 
 // HSE is 12MHz
@@ -53,6 +52,12 @@
 #define MICROPY_HW_SPI2_MISO (pin_B14)
 #define MICROPY_HW_SPI2_MOSI (pin_B15)
 
+// CAN busses
+#define MICROPY_HW_CAN1_TX (pin_B9)
+#define MICROPY_HW_CAN1_RX (pin_B8)
+#define MICROPY_HW_CAN2_TX (pin_B13)
+#define MICROPY_HW_CAN2_RX (pin_B12)
+
 // USRSW is pulled low. Pressing the button makes the input go high.
 #define MICROPY_HW_USRSW_PIN        (pin_A0)
 #define MICROPY_HW_USRSW_PULL       (GPIO_NOPULL)

ports/stm32/boards/PYBV10/mpconfigboard.h

@@ -10,7 +10,6 @@
 #define MICROPY_HW_ENABLE_RTC       (1)
 #define MICROPY_HW_ENABLE_SERVO     (1)
 #define MICROPY_HW_ENABLE_DAC       (1)
-#define MICROPY_HW_ENABLE_CAN       (1)
 #define MICROPY_HW_ENABLE_USB       (1)
 
 // HSE is 8MHz
@@ -66,8 +65,12 @@
 #define MICROPY_HW_SPI2_MOSI (pin_B15) // Y8
 
 // CAN busses
-#define MICROPY_HW_CAN1_NAME "YA" // CAN1 on RX,TX = Y3,Y4 = PB8,PB9
-#define MICROPY_HW_CAN2_NAME "YB" // CAN2 on RX,TX = Y5,Y6 = PB12,PB13
+#define MICROPY_HW_CAN1_NAME "YA"
+#define MICROPY_HW_CAN1_TX   (pin_B9) // Y4
+#define MICROPY_HW_CAN1_RX   (pin_B8) // Y3
+#define MICROPY_HW_CAN2_NAME "YB"
+#define MICROPY_HW_CAN2_TX   (pin_B13) // Y6
+#define MICROPY_HW_CAN2_RX   (pin_B12) // Y5
 
 // USRSW has no pullup or pulldown, and pressing the switch makes the input go low
 #define MICROPY_HW_USRSW_PIN        (pin_B3)

ports/stm32/boards/PYBV11/mpconfigboard.h

@@ -10,7 +10,6 @@
 #define MICROPY_HW_ENABLE_RTC       (1)
 #define MICROPY_HW_ENABLE_SERVO     (1)
 #define MICROPY_HW_ENABLE_DAC       (1)
-#define MICROPY_HW_ENABLE_CAN       (1)
 #define MICROPY_HW_ENABLE_USB       (1)
 
 // HSE is 12MHz
@@ -66,8 +65,12 @@
 #define MICROPY_HW_SPI2_MOSI (pin_B15) // Y8
 
 // CAN busses
-#define MICROPY_HW_CAN1_NAME "YA" // CAN1 on RX,TX = Y3,Y4 = PB8,PB9
-#define MICROPY_HW_CAN2_NAME "YB" // CAN2 on RX,TX = Y5,Y6 = PB12,PB13
+#define MICROPY_HW_CAN1_NAME "YA"
+#define MICROPY_HW_CAN1_TX   (pin_B9) // Y4
+#define MICROPY_HW_CAN1_RX   (pin_B8) // Y3
+#define MICROPY_HW_CAN2_NAME "YB"
+#define MICROPY_HW_CAN2_TX   (pin_B13) // Y6
+#define MICROPY_HW_CAN2_RX   (pin_B12) // Y5
 
 // USRSW has no pullup or pulldown, and pressing the switch makes the input go low
 #define MICROPY_HW_USRSW_PIN        (pin_B3)

ports/stm32/boards/PYBV3/mpconfigboard.h

@@ -9,7 +9,6 @@
 #define MICROPY_HW_ENABLE_RTC       (1)
 #define MICROPY_HW_ENABLE_SERVO     (1)
 #define MICROPY_HW_ENABLE_DAC       (1)
-#define MICROPY_HW_ENABLE_CAN       (1)
 #define MICROPY_HW_ENABLE_USB       (1)
 
 // HSE is 8MHz
@@ -57,6 +56,12 @@
 #define MICROPY_HW_SPI2_MISO (pin_B14) // Y7
 #define MICROPY_HW_SPI2_MOSI (pin_B15) // Y8
 
+// CAN busses
+#define MICROPY_HW_CAN1_TX (pin_B9) // Y4
+#define MICROPY_HW_CAN1_RX (pin_B8) // Y3
+#define MICROPY_HW_CAN2_TX (pin_B13) // Y6
+#define MICROPY_HW_CAN2_RX (pin_B12) // Y5
+
 // USRSW has no pullup or pulldown, and pressing the switch makes the input go low
 #define MICROPY_HW_USRSW_PIN        (pin_A13)
 #define MICROPY_HW_USRSW_PULL       (GPIO_PULLUP)

ports/stm32/boards/PYBV4/mpconfigboard.h

@@ -10,7 +10,6 @@
 #define MICROPY_HW_ENABLE_RTC       (1)
 #define MICROPY_HW_ENABLE_SERVO     (1)
 #define MICROPY_HW_ENABLE_DAC       (1)
-#define MICROPY_HW_ENABLE_CAN       (1)
 #define MICROPY_HW_ENABLE_USB       (1)
 
 // HSE is 8MHz
@@ -63,8 +62,12 @@
 #define MICROPY_HW_SPI2_MOSI (pin_B15) // Y8
 
 // CAN busses
-#define MICROPY_HW_CAN1_NAME "YA" // CAN1 on RX,TX = Y3,Y4 = PB8,PB9
-#define MICROPY_HW_CAN2_NAME "YB" // CAN2 on RX,TX = Y5,Y6 = PB12,PB13
+#define MICROPY_HW_CAN1_NAME "YA"
+#define MICROPY_HW_CAN1_TX   (pin_B9) // Y4
+#define MICROPY_HW_CAN1_RX   (pin_B8) // Y3
+#define MICROPY_HW_CAN2_NAME "YB"
+#define MICROPY_HW_CAN2_TX   (pin_B13) // Y6
+#define MICROPY_HW_CAN2_RX   (pin_B12) // Y5
 
 // USRSW has no pullup or pulldown, and pressing the switch makes the input go low
 #define MICROPY_HW_USRSW_PIN        (pin_B3)

ports/stm32/boards/STM32F429DISC/mpconfigboard.h

@@ -5,7 +5,6 @@
 #define MICROPY_HW_HAS_FLASH        (1)
 #define MICROPY_HW_ENABLE_RNG       (1)
 #define MICROPY_HW_ENABLE_RTC       (1)
-#define MICROPY_HW_ENABLE_CAN       (1)
 #define MICROPY_HW_ENABLE_USB       (1)
 
 // HSE is 8MHz
@@ -50,6 +49,12 @@
 //#define MICROPY_HW_SPI6_MISO    (pin_G12)
 //#define MICROPY_HW_SPI6_MOSI    (pin_G14)
 
+// CAN busses
+#define MICROPY_HW_CAN1_TX (pin_B9)
+#define MICROPY_HW_CAN1_RX (pin_B8)
+#define MICROPY_HW_CAN2_TX (pin_B13)
+#define MICROPY_HW_CAN2_RX (pin_B12)
+
 // USRSW is pulled low. Pressing the button makes the input go high.
 #define MICROPY_HW_USRSW_PIN        (pin_A0)
 #define MICROPY_HW_USRSW_PULL       (GPIO_NOPULL)

ports/stm32/boards/STM32F439/mpconfigboard.h

@@ -6,7 +6,6 @@
 #define MICROPY_HW_ENABLE_RNG       (1)
 #define MICROPY_HW_ENABLE_RTC       (1)
 #define MICROPY_HW_ENABLE_DAC       (1)
-#define MICROPY_HW_ENABLE_CAN       (1)
 #define MICROPY_HW_ENABLE_USB       (1)
 
 // SD card detect switch
@@ -75,6 +74,12 @@
 //#define MICROPY_HW_SPI6_MISO    (pin_G12)
 //#define MICROPY_HW_SPI6_MOSI    (pin_G14)
 
+// CAN busses
+#define MICROPY_HW_CAN1_TX (pin_B9)
+#define MICROPY_HW_CAN1_RX (pin_B8)
+#define MICROPY_HW_CAN2_TX (pin_B13)
+#define MICROPY_HW_CAN2_RX (pin_B12)
+
 // USRSW is pulled low. Pressing the button makes the input go high.
 #define MICROPY_HW_USRSW_PIN        (pin_A0)
 #define MICROPY_HW_USRSW_PULL       (GPIO_NOPULL)

ports/stm32/boards/STM32F4DISC/mpconfigboard.h

@@ -6,7 +6,6 @@
 #define MICROPY_HW_ENABLE_RNG       (1)
 #define MICROPY_HW_ENABLE_RTC       (1)
 #define MICROPY_HW_ENABLE_DAC       (1)
-#define MICROPY_HW_ENABLE_CAN       (1)
 #define MICROPY_HW_ENABLE_USB       (1)
 
 // HSE is 8MHz
@@ -60,6 +59,12 @@
 #define MICROPY_HW_SPI2_MISO (pin_B14)
 #define MICROPY_HW_SPI2_MOSI (pin_B15)
 
+// CAN busses
+#define MICROPY_HW_CAN1_TX (pin_B9)
+#define MICROPY_HW_CAN1_RX (pin_B8)
+#define MICROPY_HW_CAN2_TX (pin_B13)
+#define MICROPY_HW_CAN2_RX (pin_B12)
+
 // USRSW is pulled low. Pressing the button makes the input go high.
 #define MICROPY_HW_USRSW_PIN        (pin_A0)
 #define MICROPY_HW_USRSW_PULL       (GPIO_NOPULL)

ports/stm32/boards/STM32F769DISC/mpconfigboard.h

@@ -10,7 +10,6 @@
 #define MICROPY_HW_HAS_SDCARD       (1)
 #define MICROPY_HW_ENABLE_RNG       (1)
 #define MICROPY_HW_ENABLE_RTC       (1)
-#define MICROPY_HW_ENABLE_CAN       (1)
 #define MICROPY_HW_ENABLE_USB       (1)
 
 // HSE is 25MHz
@@ -44,6 +43,12 @@
 #define MICROPY_HW_SPI2_MISO        (pin_B14)
 #define MICROPY_HW_SPI2_MOSI        (pin_B15)
 
+// CAN busses
+#define MICROPY_HW_CAN1_TX          (pin_B9)
+#define MICROPY_HW_CAN1_RX          (pin_B8)
+#define MICROPY_HW_CAN2_TX          (pin_B13)
+#define MICROPY_HW_CAN2_RX          (pin_B12)
+
 // USRSW is pulled low. Pressing the button makes the input go high.
 #define MICROPY_HW_USRSW_PIN        (pin_A0)
 #define MICROPY_HW_USRSW_PULL       (GPIO_NOPULL)

ports/stm32/boards/STM32F769DISC/pins.csv

@@ -55,3 +55,5 @@ UART1_TX,PA9
 UART1_RX,PA10
 UART5_TX,PC12
 UART5_RX,PD2
+CAN2_TX,PB13
+CAN2_RX,PB12

ports/stm32/boards/STM32F7DISC/mpconfigboard.h

@@ -6,7 +6,6 @@
 #define MICROPY_HW_HAS_SDCARD       (1)
 #define MICROPY_HW_ENABLE_RNG       (1)
 #define MICROPY_HW_ENABLE_RTC       (1)
-#define MICROPY_HW_ENABLE_CAN       (1)
 #define MICROPY_HW_ENABLE_USB       (1)
 
 #define MICROPY_BOARD_EARLY_INIT    STM32F7DISC_board_early_init
@@ -50,6 +49,12 @@ void STM32F7DISC_board_early_init(void);
 #define MICROPY_HW_SPI2_MISO        (pin_B14)
 #define MICROPY_HW_SPI2_MOSI        (pin_B15)
 
+// CAN busses
+#define MICROPY_HW_CAN1_TX          (pin_B9)
+#define MICROPY_HW_CAN1_RX          (pin_B8)
+#define MICROPY_HW_CAN2_TX          (pin_B13)
+#define MICROPY_HW_CAN2_RX          (pin_B12)
+
 // USRSW is pulled low. Pressing the button makes the input go high.
 #define MICROPY_HW_USRSW_PIN        (pin_I11)
 #define MICROPY_HW_USRSW_PULL       (GPIO_NOPULL)

ports/stm32/boards/STM32F7DISC/pins.csv

@@ -51,3 +51,5 @@ USB_DM,PA11
 USB_DP,PA12
 VCP_TX,PA9
 VCP_RX,PB7
+CAN_TX,PB13
+CAN_RX,PB12

ports/stm32/boards/STM32L476DISC/mpconfigboard.h

@@ -9,7 +9,6 @@ void STM32L476DISC_board_early_init(void);
 #define MICROPY_HW_HAS_FLASH        (1)
 #define MICROPY_HW_ENABLE_RNG       (1)
 #define MICROPY_HW_ENABLE_RTC       (1)
-#define MICROPY_HW_ENABLE_CAN       (1)
 #define MICROPY_HW_ENABLE_USB       (1)
 
 // use external SPI flash for storage
@@ -58,6 +57,10 @@ extern struct _spi_bdev_t spi_bdev;
 #define MICROPY_HW_SPI2_MISO    (pin_D3)
 #define MICROPY_HW_SPI2_MOSI    (pin_D4)
 
+// CAN busses
+#define MICROPY_HW_CAN1_TX (pin_B9)
+#define MICROPY_HW_CAN1_RX (pin_B8)
+
 // Joystick is pulled low. Pressing the button makes the input go high.
 #define MICROPY_HW_USRSW_PIN        (pin_A0)
 #define MICROPY_HW_USRSW_PULL       (GPIO_NOPULL)

ports/stm32/boards/make-pins.py

@@ -16,6 +16,7 @@ SUPPORTED_FN = {
     'UART'  : ['RX', 'TX', 'CTS', 'RTS'],
     'SPI'   : ['NSS', 'SCK', 'MISO', 'MOSI'],
     'SDMMC' : ['CK', 'CMD', 'D0', 'D1', 'D2', 'D3'],
+    'CAN'   : ['TX', 'RX'],
 }
 
 CONDITIONAL_VAR = {
@@ -25,6 +26,7 @@ CONDITIONAL_VAR = {
     'UART'  : 'MICROPY_HW_UART{num}_TX',
     'USART' : 'MICROPY_HW_UART{num}_TX',
     'SDMMC' : 'MICROPY_HW_SDMMC{num}_CK',
+    'CAN'   : 'MICROPY_HW_CAN{num}_TX',
 }
 
 def parse_port_pin(name_str):

ports/stm32/can.c

@@ -104,31 +104,26 @@ STATIC uint8_t can2_start_bank = 14;
 // assumes Init parameters have been set up correctly
 STATIC bool can_init(pyb_can_obj_t *can_obj) {
     CAN_TypeDef *CANx = NULL;
-
-    uint32_t GPIO_Pin = 0;
-    uint8_t  GPIO_AF_CANx = 0;
-    GPIO_TypeDef* GPIO_Port = NULL;
     uint32_t sce_irq = 0;
+    const pin_obj_t *pins[2];
 
     switch (can_obj->can_id) {
-        // CAN1 is on RX,TX = Y3,Y4 = PB9,PB9
+        #if defined(MICROPY_HW_CAN1_TX)
         case PYB_CAN_1:
             CANx = CAN1;
-            GPIO_AF_CANx = GPIO_AF9_CAN1;
-            GPIO_Port = GPIOB;
-            GPIO_Pin = GPIO_PIN_8 | GPIO_PIN_9;
             sce_irq = CAN1_SCE_IRQn;
+            pins[0] = MICROPY_HW_CAN1_TX;
+            pins[1] = MICROPY_HW_CAN1_RX;
             __CAN1_CLK_ENABLE();
             break;
+        #endif
 
-        #if defined(CAN2)
-        // CAN2 is on RX,TX = Y5,Y6 = PB12,PB13
+        #if defined(MICROPY_HW_CAN2_TX)
         case PYB_CAN_2:
             CANx = CAN2;
-            GPIO_AF_CANx = GPIO_AF9_CAN2;
-            GPIO_Port = GPIOB;
-            GPIO_Pin = GPIO_PIN_12 | GPIO_PIN_13;
             sce_irq = CAN2_SCE_IRQn;
+            pins[0] = MICROPY_HW_CAN2_TX;
+            pins[1] = MICROPY_HW_CAN2_RX;
             __CAN1_CLK_ENABLE(); // CAN2 is a "slave" and needs CAN1 enabled as well
             __CAN2_CLK_ENABLE();
             break;
@@ -139,13 +134,13 @@ STATIC bool can_init(pyb_can_obj_t *can_obj) {
     }
 
     // init GPIO
-    GPIO_InitTypeDef GPIO_InitStructure;
-    GPIO_InitStructure.Pin = GPIO_Pin;
-    GPIO_InitStructure.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
-    GPIO_InitStructure.Mode = GPIO_MODE_AF_PP;
-    GPIO_InitStructure.Pull = GPIO_PULLUP;
-    GPIO_InitStructure.Alternate = GPIO_AF_CANx;
-    HAL_GPIO_Init(GPIO_Port, &GPIO_InitStructure);
+    uint32_t mode = MP_HAL_PIN_MODE_ALT;
+    uint32_t pull = MP_HAL_PIN_PULL_UP;
+    for (int i = 0; i < 2; i++) {
+        if (!mp_hal_pin_config_alt(pins[i], mode, pull, AF_FN_CAN, can_obj->can_id)) {
+            return false;
+        }
+    }
 
     // init CANx
     can_obj->can.Instance = CANx;

ports/stm32/mpconfigboard_common.h

@@ -57,11 +57,6 @@
 #define MICROPY_HW_ENABLE_DAC (0)
 #endif
 
-// Whether to enable the CAN peripheral, exposed as pyb.CAN
-#ifndef MICROPY_HW_ENABLE_CAN
-#define MICROPY_HW_ENABLE_CAN (0)
-#endif
-
 // Whether to enable USB support
 #ifndef MICROPY_HW_ENABLE_USB
 #define MICROPY_HW_ENABLE_USB (0)
@@ -156,6 +151,13 @@
 #define MICROPY_HW_ENABLE_HW_I2C (0)
 #endif
 
+// Enable CAN if there are any peripherals defined
+#if defined(MICROPY_HW_CAN1_TX) || defined(MICROPY_HW_CAN2_TX)
+#define MICROPY_HW_ENABLE_CAN (1)
+#else
+#define MICROPY_HW_ENABLE_CAN (0)
+#endif
+
 // Pin definition header file
 #define MICROPY_PIN_DEFS_PORT_H "pin_defs_stm32.h"
 

ports/stm32/pin_defs_stm32.h

@@ -49,6 +49,7 @@ enum {
   AF_FN_SPI,
   AF_FN_I2S,
   AF_FN_SDMMC,
+  AF_FN_CAN,
 };
 
 enum {
@@ -93,6 +94,9 @@ enum {
   AF_PIN_TYPE_SDMMC_D1,
   AF_PIN_TYPE_SDMMC_D2,
   AF_PIN_TYPE_SDMMC_D3,
+
+  AF_PIN_TYPE_CAN_TX = 0,
+  AF_PIN_TYPE_CAN_RX,
 };
 
 // The HAL uses a slightly different naming than we chose, so we provide

ports/stm32/stm32_it.c

@@ -736,7 +736,7 @@ void UART8_IRQHandler(void) {
 }
 #endif
 
-#if MICROPY_HW_ENABLE_CAN
+#if defined(MICROPY_HW_CAN1_TX)
 void CAN1_RX0_IRQHandler(void) {
     IRQ_ENTER(CAN1_RX0_IRQn);
     can_rx_irq_handler(PYB_CAN_1, CAN_FIFO0);
@@ -754,7 +754,9 @@ void CAN1_SCE_IRQHandler(void) {
     can_sce_irq_handler(PYB_CAN_1);
     IRQ_EXIT(CAN1_SCE_IRQn);
 }
+#endif
 
+#if defined(MICROPY_HW_CAN2_TX)
 void CAN2_RX0_IRQHandler(void) {
     IRQ_ENTER(CAN2_RX0_IRQn);
     can_rx_irq_handler(PYB_CAN_2, CAN_FIFO0);
@@ -772,7 +774,7 @@ void CAN2_SCE_IRQHandler(void) {
     can_sce_irq_handler(PYB_CAN_2);
     IRQ_EXIT(CAN2_SCE_IRQn);
 }
-#endif // MICROPY_HW_ENABLE_CAN
+#endif
 
 #if defined(MICROPY_HW_I2C1_SCL)
 void I2C1_EV_IRQHandler(void) {