Getting trash from SPI on SAMD21G18A (arduino-nano-33-iot)

[IchiroKuroki]

Description

When I run the test for sending data through the SPI (tests / periph_spi), garbage is written to the output buffer. If I use -1 for the cs port parameter in this test, then the board hangs. A similar effect is observed if I call spi_init_cs (0, SPI_HWCS (0)); Board - arduino-nano-33-iot(SAMD21G18A)

Steps to reproduce the issue

cd tests/periph_spi
make flash BOARD=arduino-nano-33-iot
make term BOARD=arduino-nano-33-iot

call command init:
init 0 0 0 0 14
call command send:
send TEST_DATA

Expected results

021-03-29 17:05:02,075 # .04-devel-1152-g28e6)
2021-03-29 17:05:02,076 # Manual SPI peripheral driver test (see README.md)
2021-03-29 17:05:02,077 # There are 1 SPI devices configured for your platform.
init 0 0 0 0 14
2021-03-29 17:05:22,318 # init 0 0 0 0 14
2021-03-29 17:05:22,320 # SPI_DEV(0) initialized: mode: 0, clk: 0, cs_port: 0, cs_pin: 14
send TEST_DATA
2021-03-29 17:05:37,597 # send TEST_DATA
2021-03-29 17:05:37,598 # Sent bytes
2021-03-29 17:05:37,599 # 0 1 2 3 4 5 6 7 8
2021-03-29 17:05:37,600 # 0x54 0x45 0x53 0x54 0x5f 0x44 0x41 0x54 0x41
2021-03-29 17:05:37,601 # T E S T _ D A T A
2021-03-29 17:05:37,601 #
2021-03-29 17:05:37,601 # Received bytes
2021-03-29 17:05:37,602 # 0 1 2 3 4 5 6 7 8
2021-03-29 17:05:37,603 # 0x54 0x45 0x53 0x54 0x5f 0x44 0x41 0x54 0x41
2021-03-29 17:05:37,604 # T E S T _ D A T A

Actual results

2021-03-29 17:05:02,075 # .04-devel-1152-g28e6)
2021-03-29 17:05:02,076 # Manual SPI peripheral driver test (see README.md)
2021-03-29 17:05:02,077 # There are 1 SPI devices configured for your platform.
init 0 0 0 0 14
2021-03-29 17:05:22,318 # init 0 0 0 0 14
2021-03-29 17:05:22,320 # SPI_DEV(0) initialized: mode: 0, clk: 0, cs_port: 0, cs_pin: 14
send TEST_DATA
2021-03-29 17:05:37,597 # send TEST_DATA
2021-03-29 17:05:37,598 # Sent bytes
2021-03-29 17:05:37,599 # 0 1 2 3 4 5 6 7 8
2021-03-29 17:05:37,600 # 0x54 0x45 0x53 0x54 0x5f 0x44 0x41 0x54 0x41
2021-03-29 17:05:37,601 # T E S T _ D A T A
2021-03-29 17:05:37,601 #
2021-03-29 17:05:37,601 # Received bytes
2021-03-29 17:05:37,602 # 0 1 2 3 4 5 6 7 8
2021-03-29 17:05:37,603 # 0xb0 0x07 0xcd 0xd4 0xa4 0x76 0x27 0x34 0x4c
2021-03-29 17:05:37,604 # ?? ?? ?? ?? ?? v ' 4 L

Versions

2021.01 and .04-devel-1152-g28e6

[dylad]

@IchiroKuroki
I started to look at your issue to see if there is something wrong, did you manage to fix it on your side in the mean time ?

[IchiroKuroki]

@dylad
I think I was not using this test correctly. And the expected result is not correct. I'm new to programming microcontrollers, and I didn't want to waste your time, so I closed the issue until I was sure that this was a real problem.

[dylad]

@IchiroKuroki thanks for your reply.
Feels free to reopen this if you have questions. (I'll still check on my side at some point later).

[dylad]

FYI,
I've tested tests/periph_spi on a arduino-zero clone, and issue the very same commands. It works as expected.
I suggest you to check your connection between MISO and MOSI, if MISO and MOSI are connected together, you should check your periph_conf.h to see if it match your hardware.

[IchiroKuroki]

@dylad
I checked boards/arduino-nano-33-iot/include/periph_conf.h and saw that there is a configuration defined only for SPI used to communicate with U-blox NINA-W102, soldered on the board:
static const spi_conf_t spi_config[] = {
{ /* Connected to NINA W102 */
.dev = &SERCOM4->SPI,
.miso_pin = GPIO_PIN(PA, 13),
.mosi_pin = GPIO_PIN(PA, 12),
.clk_pin = GPIO_PIN(PA, 15),
.miso_mux = GPIO_MUX_D,
.mosi_mux = GPIO_MUX_D,
.clk_mux = GPIO_MUX_D,
.miso_pad = SPI_PAD_MISO_1,
.mosi_pad = SPI_PAD_MOSI_0_SCK_3,
.gclk_src = SAM0_GCLK_MAIN,
},
};

But MISO/MOSI on pins PA16 and PA19 are also available on the board. I extended the configuration as follows:
static const spi_conf_t spi_config[] = {
{
.dev = &SERCOM3->SPI,
.miso_pin = GPIO_PIN(PA, 19),
.mosi_pin = GPIO_PIN(PA, 16),
.clk_pin = GPIO_PIN(PA, 17),
.miso_mux = GPIO_MUX_D,
.mosi_mux = GPIO_MUX_D,
.clk_mux = GPIO_MUX_D,
.miso_pad = SPI_PAD_MISO_3,
.mosi_pad = SPI_PAD_MOSI_0_SCK_1,
.gclk_src = SAM0_GCLK_MAIN,
},
{ /* Connected to NINA W102 */
.dev = &SERCOM4->SPI,
.miso_pin = GPIO_PIN(PA, 13),
.mosi_pin = GPIO_PIN(PA, 12),
.clk_pin = GPIO_PIN(PA, 15),
.miso_mux = GPIO_MUX_D,
.mosi_mux = GPIO_MUX_D,
.clk_mux = GPIO_MUX_D,
.miso_pad = SPI_PAD_MISO_1,
.mosi_pad = SPI_PAD_MOSI_0_SCK_3,
.gclk_src = SAM0_GCLK_MAIN,
},
};

And after that the test gave the expected result with init 0 0 0 0 21.
Thanks for the help!