ESP32-S3 SPI CS

[daniSi]

Dear,

we have until now successfully used the esp spi flash library on the ESP32S3-WROOM. However, now we have made a hardware change which affected only the CS pin which has moved from GPIO10 to GPIO8, and suddenly the flash stopped working. The pin is constantly 0.

We have tested the board and there is now shortcut or something else. Also when we initialize the pin as a normal output and toggle it, everything works as expected.

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const spi_bus_config_t bus_spi_config = {
			.mosi_io_num = CONFIG_SPI_PIN_MOSI, // GPIO11
			.miso_io_num = CONFIG_SPI_PIN_MISO, // GPIO13
			.sclk_io_num = CONFIG_SPI_PIN_CLK, // GPIO12
			.quadhd_io_num = -1,
			.quadwp_io_num = -1,
		};

const esp_flash_spi_device_config_t device_config = {
		.host_id = PICO_SPI_HOST,
		.cs_id = 0, // we are not shure if this has to stay 0? tried also with 1 but no change
		.cs_io_num = CONFIG_SPI_PIN_CS_FLASH, // before GPIO10, now GPIO8
		.io_mode = SPI_FLASH_DIO,
		.speed = ESP_FLASH_40MHZ,
	};

Is there maybe some pin limitation which pins can/cant be used? Thank you

[ESP_Sprite]

That is odd. Do you see any errors or warnings on the ESP serial port when booting / initing the flash?

[daniSi]

No there is everything normal on the output, until it comes to the flash initialization, where the output is:

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E (976) HW_INIT: Failed to initialize external Flash: ESP_ERR_FLASH_NOT_INITIALISED (0x6003)

for curiosity we have now try to connect also to some other GPIOs, such as: 9, 39 but it neither works. But, when we brick it back to GPIO10 as it was before it works out of the box. Also we have disabled all other peripherals, if there would be some pinoverlaping.

So the CS pin doesnt have to be specific if using the flash library? Because what has irritated us was the function use for the GPIO10 which is: RTC_GPIO10, GPIO10, TOUCH10, ADC1_CH9, FSPICS0, FSPIIO4, SUBSPICS0

[ESP_Sprite]

As far as I'm aware, the external flash library uses the SPI master driver as the underlying layer, and that is supposed to be able to allocate the pins through the GPIO matrix. I'll see if I can investigate, perhaps there's some bug in the S3 implementation.

[daniSi]

Ok, thank you for checking on this. If it helps, we are using the esp-idf v4.4.

[ESP_Sprite]

It looks like a bug in the SPI flash driver. As you are using the IOMUX pins for the bus, the driver logic erroneously assumes the CS will be an IOMUX pin as well, meaning only GPIO10 will work. A dirty hack to get around this is to open esp-idf/components/spi_flash/esp_flash_spi_init.c and locate the line

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bool use_iomux = spicommon_bus_using_iomux(config->host_id);

and put 'use_iomux=false;' under it. I'll ask my colleagues to find and integrate a better solution for this.

[daniSi]

Thank you, this has now solved the problem!

regards, Danijel