STM32F20X ADC has voltage output

This is normal. You are supposed to connect a relatively low impedance external signal source.

JW

Ive found with a stm32L432 that if you have any pins set to GPIO out then then hdac1 DAC_CHANNEL_2 is limited to 0.5 volts

if you add say PB7 as a GPIO output changeing the .ioc and letting it generate the code it changes

from

static void MX_GPIO_Init(void)

{

 /* GPIO Ports Clock Enable */

 __HAL_RCC_GPIOA_CLK_ENABLE();

}

to

static void MX_GPIO_Init(void)

{

 GPIO_InitTypeDef GPIO_InitStruct = {0};

 /* GPIO Ports Clock Enable */

 __HAL_RCC_GPIOA_CLK_ENABLE();

 __HAL_RCC_GPIOB_CLK_ENABLE();

 /*Configure GPIO pin Output Level */

 HAL_GPIO_WritePin(GPIOB, GPIO_PIN_7, GPIO_PIN_RESET);

 /*Configure GPIO pin : PB7 */

 GPIO_InitStruct.Pin = GPIO_PIN_7;

 GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;

 GPIO_InitStruct.Pull = GPIO_NOPULL;

 GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;

 HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);

}

The output on hdac1 DAC_CHANNEL_2 is limited to justo over 0.5 of a volt. this appears to be consistent for all ports I have tried so far. It doesnt appear to be documented at least Ive not been able to find any thing

Further it appears to be __HAL_RCC_GPIOA_CLK_ENABLE(); which refers to

in Drivers\STM32L4xx_HAL_Driver\Inc\stm32l4xx_hal_rcc.h

#define __HAL_RCC_GPIOB_CLK_ENABLE()      do { \

                         __IO uint32_t tmpreg; \

                         SET_BIT(RCC->AHB2ENR, RCC_AHB2ENR_GPIOBEN); \

                         /* Delay after an RCC peripheral clock enabling */ \

                         tmpreg = READ_BIT(RCC->AHB2ENR, RCC_AHB2ENR_GPIOBEN); \

                         UNUSED(tmpreg); \

                        } while(0)

Which is clever white mans magic that looks like its some registery update

Any way it appears to break hdac1 DAC_CHANNEL_2 full range

Please don't hijack older threads, start your own, stating what hardware are you using, which STM32, what is the program, what are the symptoms and how are they different from the expectations.

JW

Having a look at the schematic it looks like there are 2 jumpers on the back of the board SB18 Connect D4 to A4 and SB16 Connect D5 to A5 if you want to use A4 (PA5) as an analoge output or a5 as an ADC these jumbers neet to be removed