Pin Mapping on L4R5ZI

[PerennialNovice]

I'm still trying to create a custom variant and therefore am looking at the files for Nucelo-L4R5ZI and the corresponding generic variant.
I don't understand how pin mappings are made.

For the generic it seems that ADC1IN_1 is mapped to PA0

Arduino_Core_STM32/variants/STM32L4xx/L4R5Z(G-I)T_L4R7ZIT_L4S5ZIT_L4S7ZIT/variant_generic.h

Line 18 in b8756be

#define PA0 PIN_A0

For nucleo it is mapped to PA3

Arduino_Core_STM32/variants/STM32L4xx/L4R5Z(G-I)T_L4R7ZIT_L4S5ZIT_L4S7ZIT/variant_NUCLEO_L4R5ZI.h

Line 129 in b8756be

#define PA3 PIN_A0

In general the mappings for analog inputs does not correspond to the datasheet where ADC1IN_1 is said to be on pin PC0

Am I making false assumptions or is this an error?
If I got it wrong, please spare a minute to explain.

Thanks!

[fpistm]

Hi @MasteringTheMess
There is no link between PIN_Ax and the ADCx peripheral and channel.
PIN_Ax means the pin is defined to be the analog pin number Ax in Arduino naming.

You use it like this for the NUCLEO_L4R5ZI:
analogRead(A0); or analogRead(PA3); or analogRead(0); or analogRead(D107);

then the core will search in the PinMap_ADC array of the PeripheralPins.c which peripheral have to be used

Arduino_Core_STM32/variants/STM32L4xx/L4R5Z(G-I)T_L4R7ZIT_L4S5ZIT_L4S7ZIT/PeripheralPins.c

Lines 36 to 54 in b8756be

	WEAK const PinMap PinMap_ADC[] = {
	{PA_0, ADC1, STM_PIN_DATA_EXT(STM_MODE_ANALOG, GPIO_NOPULL, 0, 5, 0)}, // ADC1_IN5
	{PA_1, ADC1, STM_PIN_DATA_EXT(STM_MODE_ANALOG, GPIO_NOPULL, 0, 6, 0)}, // ADC1_IN6
	{PA_2, ADC1, STM_PIN_DATA_EXT(STM_MODE_ANALOG, GPIO_NOPULL, 0, 7, 0)}, // ADC1_IN7
	{PA_3, ADC1, STM_PIN_DATA_EXT(STM_MODE_ANALOG, GPIO_NOPULL, 0, 8, 0)}, // ADC1_IN8
	{PA_4, ADC1, STM_PIN_DATA_EXT(STM_MODE_ANALOG, GPIO_NOPULL, 0, 9, 0)}, // ADC1_IN9
	{PA_5, ADC1, STM_PIN_DATA_EXT(STM_MODE_ANALOG, GPIO_NOPULL, 0, 10, 0)}, // ADC1_IN10
	{PA_6, ADC1, STM_PIN_DATA_EXT(STM_MODE_ANALOG, GPIO_NOPULL, 0, 11, 0)}, // ADC1_IN11
	{PA_7, ADC1, STM_PIN_DATA_EXT(STM_MODE_ANALOG, GPIO_NOPULL, 0, 12, 0)}, // ADC1_IN12
	{PB_0, ADC1, STM_PIN_DATA_EXT(STM_MODE_ANALOG, GPIO_NOPULL, 0, 15, 0)}, // ADC1_IN15
	{PB_1, ADC1, STM_PIN_DATA_EXT(STM_MODE_ANALOG, GPIO_NOPULL, 0, 16, 0)}, // ADC1_IN16
	{PC_0, ADC1, STM_PIN_DATA_EXT(STM_MODE_ANALOG, GPIO_NOPULL, 0, 1, 0)}, // ADC1_IN1
	{PC_1, ADC1, STM_PIN_DATA_EXT(STM_MODE_ANALOG, GPIO_NOPULL, 0, 2, 0)}, // ADC1_IN2
	{PC_2, ADC1, STM_PIN_DATA_EXT(STM_MODE_ANALOG, GPIO_NOPULL, 0, 3, 0)}, // ADC1_IN3
	{PC_3, ADC1, STM_PIN_DATA_EXT(STM_MODE_ANALOG, GPIO_NOPULL, 0, 4, 0)}, // ADC1_IN4
	{PC_4, ADC1, STM_PIN_DATA_EXT(STM_MODE_ANALOG, GPIO_NOPULL, 0, 13, 0)}, // ADC1_IN13
	{PC_5, ADC1, STM_PIN_DATA_EXT(STM_MODE_ANALOG, GPIO_NOPULL, 0, 14, 0)}, // ADC1_IN14
	{NC, NP, 0}
	};

In our case PA3 is ADC1_IN8

Arduino_Core_STM32/variants/STM32L4xx/L4R5Z(G-I)T_L4R7ZIT_L4S5ZIT_L4S7ZIT/PeripheralPins.c

Line 40 in b8756be

{PA_3, ADC1, STM_PIN_DATA_EXT(STM_MODE_ANALOG, GPIO_NOPULL, 0, 8, 0)}, // ADC1_IN8

[PerennialNovice]

Thanks a lot @fpistm !

Now I understand how this works :)