Wrong values in g_ADigitalPinMap?

[henrygab]

It appears that five pins are listed twice in the pin map for the Feather nRF52840 Express:

Adafruit_nRF52_Arduino/variants/feather_nrf52840_express/variant.cpp

Lines 34 to 36 in b6a8566

	47, // D3 is LED1 on P1.15
	42, // D4 is LED2 on P1.10
	40, // D5 on P1.08

Adafruit_nRF52_Arduino/variants/feather_nrf52840_express/variant.cpp

Line 38 in b6a8566

34, // D7 is Button on P1.02

Adafruit_nRF52_Arduino/variants/feather_nrf52840_express/variant.cpp

Line 44 in b6a8566

41, // D13 on P1.09

These pins are listed a second time at their own index:

Adafruit_nRF52_Arduino/variants/feather_nrf52840_express/variant.cpp

Lines 70 to 71 in b6a8566

	33, 34, 35, 36, 37, 38, 39,
	40, 41, 42, 43, 44, 45, 46, 47

Is this intentional? This seems like it may be a bug....

[henrygab]

A potential reason that five PORT.PIN were duplicated is now known.
The board has 48 pins, so the definition of the pin map may have started with the presumption that all 48 pins should be listed, and thus started the mapping with identity mapping (i.e., g_ADigitalPinMap[i] == i). After then editing the file to list all the pins deemed usable, the remaining entries in g_ADigitalPinMap may have been left at the identity mapping.

Here are the five PORT.PIN that are not included in the current g_ADigitalPinMap:

PORT.PIN	Purpose	Schematic	Usable by sketches
0.00	XL1	32.768kHz crystal	False
0.01	XL2	32.768kHz crystal	False
0.09	NFC1	TP1	Via solderable point
0.18	RESET	reset switch	False
1.00	SWO	SWD Debugger	False
1.01	GPIO	Not Connected	False

Of these, only NFC1 (0.09) should likely be included in the pin map.

There are also problems with the pins listed for NFC1 and NFC2:

Adafruit_nRF52_Arduino/variants/feather_nrf52840_express/variant.h

Lines 91 to 92 in b6a8566

	#define PIN_NFC1 (2)
	#define PIN_NFC2 (51)

Adafruit_nRF52_Arduino/variants/feather_nrf52840_express/variant.cpp

Lines 29 to 33 in b6a8566

	const uint32_t g_ADigitalPinMap[] =
	{
	25, // D0 is UART TX on P0.25
	24, // D1 is UART RX on P0.24
	10, // D2 is on P0.10

As can be seen, PIN_NFC1 is defined to be 2 in variant.h, and variant.cpp maps pin 2 to 0.10, but the schematic and nRF52840 specification show NFC1 to be 0.09.
As can also be seen, PIN_NFC2 is defined to be 51 in variant.h, which is beyond the valid indices of the pin map.

Fixing the variant.cpp files seems necessary for NFC (see #31).

[hathach]

thanks @henrygab it is indeed an issue, the header declare more pins that the board actually expose. I will check out the schematics with your PR.