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arduino / ArduinoCore-samd

Arduino Core for SAMD21 CPU
GNU Lesser General Public License v2.1
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Correct pin for SD SPI on MKRZERO #500

Closed tushar-semwal closed 4 years ago

tushar-semwal commented 4 years ago

There is a bit confusion on the actual SD SPI pins on MKRZERO: the variant.h file says:

// SPI1: Connected to SD
#define PIN_SPI1_MISO (29u)
#define PIN_SPI1_MOSI (26u)
#define PIN_SPI1_SCK  (27u)
#define PIN_SPI1_SS   (28u)
#define PERIPH_SPI1   sercom4

While the variant.cpp in the comment section mentions:

/*
 +------------+------------------+--------+-----------------+--------+-----------------------+---------+---------+--------+--------+----------+----------+
 | Pin number |  MKR  Board pin  |  PIN   | Notes           | Peri.A |     Peripheral B      | Perip.C | Perip.D | Peri.E | Peri.F | Periph.G | Periph.H |
 |            |                  |        |                 |   EIC  | ADC |  AC | PTC | DAC | SERCOMx | SERCOMx |  TCCx  |  TCCx  |    COM   | AC/GLCK  |
 |            |                  |        |                 |(EXTINT)|(AIN)|(AIN)|     |     | (x/PAD) | (x/PAD) | (x/WO) | (x/WO) |          |          |
 +------------+------------------+--------+-----------------+--------+-----+-----+-----+-----+---------+---------+--------+--------+----------+----------+
 |            | SD SPI           |        |                 |        |     |     |     |     |         |         |        |        |          |          |
 | 26         |                  |  PA12  | SD SCK          |   12   |     |     |     |     |  *2/00  |   4/00  | TCC2/0 | TCC0/6 |          | AC/CMP0  |
 | 27         |                  |  PA13  | SD MOSI         |   13   |     |     |     |     |  *2/01  |   4/01  | TCC2/1 | TCC0/7 |          | AC/CMP1  |
 | 28         |                  |  PA14  | SD SS           |   14   |     |     |     |     |   2/02  |   4/02  |  TC3/0 | TCC0/4 |          | GCLK_IO0 |
 | 29         |                  |  PA15  | SD MISO         |   15   |     |     |     |     |  *2/03  |   4/03  |  TC3/1 | TCC0/5 |          | GCLK_IO1 |
 | 30         |                  |  PA27  | SD CD           |   15   |     |     |     |     |         |         |        |        |          | GCLK_IO0 |
 +------------+------------------+--------+-----------------+--------+-----+-----+-----+-----+---------+---------+--------+--------+----------+----------+

I can see a swap in pin 26 and 27.

Whats the actual one?

facchinm commented 4 years ago

variant.h is correct; the comment on variant.cpp should be fixed since PA12 is MOSI and PA13 is SCK in the particular mux we chose. @Rocketct