Interrupt issues with the STM32F411VE with Arduino Framework

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I have developed a custom board using an STM32F411VET6, and I am having issues with getting everything working properly on the board. I found a similar board, and modified it. It works, but there are two issues. One is just minor, but one is a show stopper.

The minor issue is that all pins >PB_11 are off by one. I can deal with that. A more major issue for me is that I am having major issues with with interrupts on pin state change. Essentially, I want to have interrupts on state change of 16 pins.

If I use the following code, it works… It is operating on PE_1.

    stm32_interrupt_enable((GPIO_TypeDef *)GPIOE_BASE, GPIO_PIN_1, pinStateChanged_A0, GPIO_MODE_IT_RISING_FALLING);

If I then use the following code, the previous interrupt stops working, and this newer one works.

stm32_interrupt_enable((GPIO_TypeDef *)GPIOD_BASE, GPIO_PIN_1, pinStateChanged_C1, GPIO_MODE_IT_RISING_FALLING);

Here is the relevant part of my platformio.ini file

[env:AlarmOctopus_pcbv1]
platform = ststm32
board = generic
framework = arduino
platform_packages = toolchain-gccarmnoneeabi@1.90201.191206

This points to the following generic.json file

{
	"build": {
	  "core": "stm32",
	  "cpu": "cortex-m4",
	  "extra_flags": "-DSTM32F411xE -DSTM32F4xx -DARDUINO_GENERIC_F411VETX ",
	  "f_cpu": "100000000L",
	  "mcu": "stm32f411vet6",
	  "product_line": "STM32F411xE",
	  "variant": "STM32F4xx/F411V(C-E)T"
	},
	"debug": {
	  "jlink_device": "STM32F411VE",
	  "openocd_target": "stm32f4x",
	  "svd_path": "STM32F411xx.svd"
	},
	"frameworks": [
	  "arduino",
	  "cmsis",
	  "stm32cube",
	  "libopencm3"
	],
	"name": "STM32F411VE (128k RAM. 512k Flash)",
	"upload": {
	  "maximum_ram_size": 131072,
	  "maximum_size": 524288,
	  "protocol": "stlink",
	  "protocols": [
		"blackmagic",
		"dfu",
		"jlink",
		"serial",
		"stlink"
	  ]
	},
	"url": "https://www.st.com/en/microcontrollers-microprocessors/stm32f411re.html",
	"vendor": "Generic"
  }

To get this to work, I needed to generate a ldscript.ld using STM32Cube and place it in .platformio/packages/framework-arduinoststm32/variants/STM32F4xx/F411V(C-E)T. Like I noted, the only issues I am seeing are with pin numbering and interrupts.

EDIT: If I use something like attachInterrupt(digitalPinToInterrupt(reader[2].in_D1), pinStateChanged_C1, CHANGE); I am still getting exactly the same issue. From further reading, there are a limited number of hardware interrupts; and it appears that all the 0 pins (PA_0, PB_0, …) should share the same interrupt. So should all the 1 pins (PA_1, PB_2, …) and so forth. It further appears that the software architecture should be rather smart, and then forward the hardware interrupts on. I have no idea why the latest attachInterrupt for a pin set is the only one that is working.

Any assistance would be appreciated. Thanks.

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Exactly. On STM32, one EXTI hardware block, e.g., EXTI0, manages all the pins PA0, PB0, PC0, PD0, PE0, et cetera. There should be EXTI0 to EXTI15 available in hardware. See https://stackoverflow.com/a/36440626/5296568.

3

Thanks so much for that. It just confirmed what I was seeing, and I couldn’t quite get my head around the software architecture being not having implemented something so visible. A chip limitation makes sense. I guess I will be doing a new prototype. I have other mods to make anyway.

Checking the reference manual does indeed mention that in the EXTI section. The important part is the diagram ‘External interrupt/event GPIO mapping’ (Figure 30), which has only four bits coming from the SYSCFG_EXTICRx register despite there being more than four pins to select from. Looking further, section 7.2.3 shows how SYSCFG_EXTICR1 is configured.

My confusion was that the datasheet suggested that ’ Up to 81 GPIOs can be connected to the 16 external interrupt lines.'. It just didn’t say that they could be connected simultaneously.