Using External NOR Flash on SDK3.1

Question

Hello,

I am in the process of upgrading our product from SDK 1.6.1 to the latest SDK (3.1 at time of writing). I am quite lost on the external flash through using devicetree. I managed it in 1.6.1, but it was a long time ago and things seem a little different. I have also looked on other questions here and they either aren't describing my issue or they are older SDKs with irrelevant information.

We have a board based on the nrf9160DK, which I have always just used an overlay file to note the changes, and disable things that aren't needed. That has worked for everything else so far.

From the samples, it looks like I just need to have the SPI enabled, and the have the driver selected, and in the configuration file I basically just need CONFIG_FLASH=y to enable it to work.

I am pretty sure I have the overlay file correct, it's pretty much the same in SDK1.6.1, except we now use pinctrl.

&pinctrl {
	uart3_default: uart3_default {
		group1 {
			psels = <NRF_PSEL(UART_TX, 0, 31)>, <NRF_PSEL(UART_RX, 0, 30)>;
		};
	};

	uart3_sleep: uart3_sleep {
		group1 {
			psels = <NRF_PSEL(UART_TX, 0, 31)>;
		};
	};

	spi1_default: spi1_default {
		group1 {
			psels = <NRF_PSEL(SPIM_MISO, 0, 4)>,
					<NRF_PSEL(SPIM_MOSI, 0, 3)>,
					<NRF_PSEL(SPIM_SCK, 0, 2)>;
		};
	};

	spi1_sleep: spi1_sleep {
		group1 {
			psels = <NRF_PSEL(SPIM_MISO, 0, 4)>;
		};
	};
};

&spi1 {
	compatible = "nordic,nrf-spim";
	status = "okay";
	pinctrl-0 = <&spi1_default>;
	pinctrl-1 = <&spi1_sleep>;
	pinctrl-names = "default", "sleep";
	cs-gpios = < &gpio0 8 GPIO_ACTIVE_LOW >;	//22003 HW P0.08, 21014 HW P0.01
	mx25r64: mx25r6435f@0 {
		compatible = "jedec,spi-nor";
		reg = < 0x0 >;
		spi-max-frequency = <DT_FREQ_M(8)>;
		label = "MX25R64_2";
		jedec-id = [ C2 28 17 ];
		sfdp-bfp = [ E5 20 F1 FF 	 FF FF FF 03 	 44 EB 08 6B 	 08 3B 04 BB 
					 EE FF FF FF 	 FF FF 00 FF 	 FF FF 00 FF 	 0C 20 0F 52 
					 10 D8 00 FF 	 23 72 F5 00 	 82 ED 04 CC 	 44 83 68 44 
					 30 B0 30 B0 	 F7 C4 D5 5C 	 00 BE 29 FF 	 F0 D0 FF FF ];
		size = < 0x4000000 >;
		has-dpd;
		t-enter-dpd = < 0x2710 >;
		t-exit-dpd = < 0x88b8 >;
	};
};

With the SPI_FLASH sample, I can get this to build, but as soon as I try and debug it, there is an exception in the pre-kernel TF-M ns boot phase. It gets trapped in

tfm_ns_fault_handler_callback(), which I assume means there is some problem with doing something in the secure/non-secure parts of the code.

In my other project that I am working on, as soon as I add CONFIG_FLASH, I find the exact same thing happens, so I think that is where the problem lies. I am not totally sure if there are other configuration macros I need, as most of them seem to relate to DFU, and allowing booting from an image on an external flash.

To be clear, I am using external flash to read/write my own data, I just want the devicetree to sort out the jedec driver, so I can just call functions like flash_read()

Thanks in advance,

Damien

Hakon · Accepted Answer

Maybe the problem is that in TFM uart1 is enabled, and that is causing problems since spi1 is also enabled. If you want you can disable TFM logging and then enable spi1 if you want to test if this is actually happening. You can set 
 CONFIG_TFM_LOG_LEVEL_SILENCE=y

Using External NOR Flash on SDK3.1

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