nRF5340 1-wire EEPROM

[.....]

Hello,

I have nrf5340dk and AT21CS01-STUM10-T module. This is EEPROM module. I want to communicate with it by 1-wire. 
The problem is that I don't know how to do it. I looked through examples in SDK and DevZone but didn't find anything helpful for me. I found an example with 1-wire in the SDK (v2.8.0), but there is very short code in it and there is no overlay for Nordic board. I see that this example uses the w1 driver. When I looked at the w1.h file, I saw functions for writing and reading, but I didn't try them because I don't know how .overlay file for 1-wire should look like.

Can you help me with it ?

Best Regards

[Håkon Alseth]

Hi,

 

Zephyr has a 1-wire scanner sample available here:

https://docs.zephyrproject.org/latest/samples/drivers/w1/scanner/README.html#w1-scanner

 

You can setup a overlay for your board similar to this:

&uart1 {
	status = "okay";
	current-speed = <115200>;
	pinctrl-0 = <&uart1_default>;
	pinctrl-1 = <&uart1_sleep>;
	pinctrl-names = "default", "sleep";
	w1: w1 {
		compatible = "zephyr,w1-serial";
	};    
};

&pinctrl {
	uart1_default: uart1_default {
		group1 {
			psels = <NRF_PSEL(UART_TX, 1, 9)>;
		};
		group2 {
			psels = <NRF_PSEL(UART_RX, 1, 8)>;
			bias-pull-up;
		};
	};
	uart1_sleep: uart1_sleep {
		group1 {
			psels = <NRF_PSEL(UART_TX, 1, 9)>,
				<NRF_PSEL(UART_RX, 1, 8)>;
			low-power-enable;
		};
	};    
};

 

Feel free to change the pinout to your liking.

 

Kind regards,

Håkon

[.....]

Hi,

Thanks for your reply.

I tried to use 1w library with my module, but it didn't work.

Then i found this site
AT21CS01 | Microchip Technology
and I downloaded this code:
https://ww1.microchip.com/downloads/aemDocuments/documents/MPD/ApplicationNotes/AppnoteSourceCode/AN3304_Source_Code_V1.0.0.X.zip

I ported this code (only low-level.h, low-level.c, operations.h, operations.c files) to ESP32 and it works.
Then I ported this code to nordic (for now nRF52840dk). But I have problem - my code read only "0xFF" value when EEPROM is connected (or 0x00 when pin is connected to GND). I was checking with Logic Analyzer how single wire signal looks and it is similar to the one generated by ESP (times are also similar).
I think this problem is caused by pin configuration.

This is my .overlay file

/ {
	m_pin {
		compatible = "gpio-leds";
		m_pin0: m_pin_0 {
			gpios = <&gpio0 29 (GPIO_OPEN_DRAIN | GPIO_PULL_UP)>;
			label = "M_PIN";
		};
	};

	aliases {
		mpin = &m_pin0;
	};
};

and I have this lines in my code:

int ret;

if (!gpio_is_ready_dt(&mypin)) {
	return -1;
}

ret = gpio_pin_configure_dt(&mypin, GPIO_INPUT | GPIO_OUTPUT | GPIO_OPEN_DRAIN | GPIO_PULL_UP);
if (ret < 0) {
	return -1;
}

I also tried to switching pin_configure_dt depending on writing and reading from module but it didn't help.

// before writing to module
//ret = gpio_pin_configure_dt(&mypin, GPIO_INPUT | GPIO_OPEN_DRAIN | GPIO_PULL_UP); // I had an error with this line
ret = gpio_pin_configure_dt(&mypin, GPIO_OUTPUT | GPIO_INPUT | GPIO_OPEN_DRAIN | GPIO_PULL_UP);
//ret = gpio_pin_configure_dt(&mypin, GPIO_INPUT); // I also tried this - but then in .overlay file was this line: 'gpios = <&gpio0 29 (GPIO_PULL_UP)>;'
if (ret < 0) {
    printk("\n\tERROR: configure INPUT\n");
}



// before reading from module
ret = gpio_pin_configure_dt(&mypin, GPIO_OUTPUT | GPIO_OPEN_DRAIN | GPIO_PULL_UP);
if (ret < 0) {
    printk("\n\tERROR: configure OUTPUT\n");
}

Can you help me with it ?

Best Regards

[Håkon Alseth]

Hi,

 

Reading a pin is either '0' or '1'. You will not get a serialized data output without fully bit-banging your chosen protocol. I would recommend that you look into the former w1-scanner and try to get that running instead of just reading a gpio input.

 

Kind regards,

Håkon

[.....]

Hi,

But problem is that w1-scanner doesn't work with my module.

With the configuration you wrote above I have this output (when my module is connected):
[00:00:00.251,220] <inf> main: Number of devices found on bus: 0
and this when nothng is connected to port P1.08:
[00:00:00.254,791] <err> w1_serial: tx_rx_error reset_present
[00:00:00.254,791] <inf> main: Number of devices found on bus: -5

Second thing is that I want to read and write data, and this functionality is not presented in this sample.

I have the above code which I tested with ESP and it works with my EEPROM module, so I would like to implement this code on nrf but I have problem that nrf is not reading data from EEPROM.


Can you help me with it ?

Best Regards