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Issue: Wrong InterruptIn with pullup configuration in NUCLEO-F103RB
Hi, I'm working with NUCLEO-F103RB and I've found problems setting InterruptIn with pullup using mbed-src source code. I'll try to explain what is happening:
InterruptInt trig(PA_4);
void handleISR(){
}
int main(){
trig.fall(&handleISR);
trig.enable_irq();
trig.mode(PullUp);
while(1){
}
}
The problem I've found is that, by default after reset, PA_4 as other input pins is setup as Input floating (you can see it in register bits GPIOA_CRL.CNF4[1:0] = 01.
When you select it as InterruptIn, this configuration is kept. Nevertheless when mode is changed to PullUp, only bit1 of GPIOA_CRL.CNF4[1:0] is set, but bit0 is not reset. So now, this register is changed to GPIOA_CRL.CNF4[1:0]=11. Which corresponds to "Reserved" in stead of "Input with pullup or pull down". And then PA_4 is not properly configured.
On the other hand, pull up/down is selected with register GPIOA_ODR, so if GPIOA_ODR.bit4 = 1 then pull up, else if GPIOA_ODR.bit4 = 0 then pull down. And this setup is never done in current mbed-src release.
Current gpio mode configuration in mbed-src is done in file pinmap.c, function: pin_mode, see below:
void pin_mode(PinName pin, PinMode mode)
{
MBED_ASSERT(pin != (PinName)NC);
uint32_t port_index = STM_PORT(pin);
uint32_t pin_index = STM_PIN(pin);
// Enable GPIO clock
uint32_t gpio_add = Set_GPIO_Clock(port_index);
GPIO_TypeDef *gpio = (GPIO_TypeDef *)gpio_add;
// Configure open-drain and pull-up/down
switch (mode) {
case PullNone:
break;
case PullUp:
case PullDown:
// Set pull-up / pull-down for Input mode
if (pin_index < 8) {
if ((gpio->CRL & (0x03 << (pin_index * 4))) == 0) { // MODE bits = Input mode
gpio->CRL |= (0x08 << (pin_index * 4)); // Set pull-up / pull-down
}
} else {
if ((gpio->CRH & (0x03 << ((pin_index % 8) * 4))) == 0) { // MODE bits = Input mode
gpio->CRH |= (0x08 << ((pin_index % 8) * 4)); // Set pull-up / pull-down
}
}
break;
case OpenDrain:
// Set open-drain for Output mode (General Purpose or Alternate Function)
if (pin_index < 8) {
if ((gpio->CRL & (0x03 << (pin_index * 4))) > 0) { // MODE bits = Output mode
gpio->CRL |= (0x04 << (pin_index * 4)); // Set open-drain
}
} else {
if ((gpio->CRH & (0x03 << ((pin_index % 8) * 4))) > 0) { // MODE bits = Output mode
gpio->CRH |= (0x04 << ((pin_index % 8) * 4)); // Set open-drain
}
}
break;
default:
break;
}
}
In order to solve this configuration defect, I've modified this function by myself and now is working properly, see it below:
void pin_mode(PinName pin, PinMode mode)
{
MBED_ASSERT(pin != (PinName)NC);
uint32_t port_index = STM_PORT(pin);
uint32_t pin_index = STM_PIN(pin);
// Enable GPIO clock
uint32_t gpio_add = Set_GPIO_Clock(port_index);
GPIO_TypeDef *gpio = (GPIO_TypeDef *)gpio_add;
// Configure open-drain and pull-up/down
switch (mode) {
case PullNone:
break;
case PullUp:
case PullDown:
// Set pull-up / pull-down for Input mode
if (pin_index < 8) {
if ((gpio->CRL & (0x03 << (pin_index * 4))) == 0) { // MODE bits = Input mode
gpio->CRL |= (0x08 << (pin_index * 4)); // Set pull-up / pull-down
gpio->CRL &= ~(0x08 << ((pin_index * 4)-1)); //<-- ADDED LINE: ENSURES GPIOx_CRL.CNFx.bit0 = 0
}
} else {
if ((gpio->CRH & (0x03 << ((pin_index % 8) * 4))) == 0) { // MODE bits = Input mode
gpio->CRH |= (0x08 << ((pin_index % 8) * 4)); // Set pull-up / pull-down
gpio->CRH &= ~(0x08 << (((pin_index % 8) * 4)-1)); //<-- ADDED LINE: ENSURES GPIOx_CRH.CNFx.bit0 = 0
}
}
//<-- ADDED LINES: ENSURES GPIOx_ODR pull up/down is properly setup
if(mode == PullUp)
gpio->ODR |= (0x01 << (pin_index)); // Set pull-up
else
gpio->ODR &= ~(0x01 << (pin_index)); // Set pull-down
break;
case OpenDrain:
// Set open-drain for Output mode (General Purpose or Alternate Function)
if (pin_index < 8) {
if ((gpio->CRL & (0x03 << (pin_index * 4))) > 0) { // MODE bits = Output mode
gpio->CRL |= (0x04 << (pin_index * 4)); // Set open-drain
}
} else {
if ((gpio->CRH & (0x03 << ((pin_index % 8) * 4))) > 0) { // MODE bits = Output mode
gpio->CRH |= (0x04 << ((pin_index % 8) * 4)); // Set open-drain
}
}
break;
default:
break;
}
}
Just with those modifications, InterruptIn with PullUp mode is setup properly. Kind regards. Raul.
Thanks for reporting. CAn you please add this to the issues on github https://github.com/mbedmicro/mbed/issues ? Or if you find time, you can send a pull request with your fix, the one you presented above.
I can add it there to the issues and reference this report there.
Regards, 0xc0170