Configuring SSD1306 shield with 64x32 pixel display.

RE: Configuring SSD1306 shield with 64x32 pixel display.

LampLighter — Fri, 19 Jul 2024 19:35:52 GMT

Hello,

I haven't had any time to test it out recently so I will close this ticket for now.

Thank you!

RE: Configuring SSD1306 shield with 64x32 pixel display.

Jørgen Holmefjord — Fri, 19 Jul 2024 11:32:58 GMT

Hi,

Did you manage to resolve this issue, or do you need more help from us?

Best regards,
Jørgen

RE: Configuring SSD1306 shield with 64x32 pixel display.

LampLighter — Wed, 24 Apr 2024 01:31:10 GMT

HI Jørgen,

Attached is the project folder. I am building with the nrf52dk_nrf52832 board. The breakpoint gets hit and there are multiple functions that are called before it.

Also it turns out that my temporary "solution" only works for the text labels set in main(). Anything added afterwards shows up broken on the screen (similar to what it looked before the temp fix)

Project folder:

devzone.nordicsemi.com/.../3302.lvgl.zip

In the attached solution I modified some lines in the ssd1306_write_default to be able to change the "x" value dynamically with "segment offset" in the devicetree.

RE: Configuring SSD1306 shield with 64x32 pixel display.

Jørgen Holmefjord — Mon, 22 Apr 2024 14:42:34 GMT

Hi,

Can you debug the application and set a breakpoint in ssd1306_write_default() to see where it is being called from? I tried this with the default sample, but the breakpoint was never hit.

Have you made any other modifications to the libraries or sources?

Best regards,
Jørgen

RE: Configuring SSD1306 shield with 64x32 pixel display.

LampLighter — Sun, 21 Apr 2024 21:43:08 GMT

I have found a temporary solution. In zephyr/drivers/display/ssd1306.c, change these lines:

static int ssd1306_write_default(const struct device *dev, const uint16_t x, const uint16_t y,
				 const struct display_buffer_descriptor *desc, const void *buf,
				 const size_t buf_len)
{
	uint8_t cmd_buf[] = {
		SSD1306_SET_MEM_ADDRESSING_MODE,
		SSD1306_ADDRESSING_MODE,
		SSD1306_SET_COLUMN_ADDRESS,
		x,
		(x + desc->width - 1),
		SSD1306_SET_PAGE_ADDRESS,
		y/8,
		((y + desc->height)/8 - 1)
	};

to this:

static int ssd1306_write_default(const struct device *dev, const uint16_t y,
				 const struct display_buffer_descriptor *desc, const void *buf,
				 const size_t buf_len)
{
	uint8_t cmd_buf[] = {
		SSD1306_SET_MEM_ADDRESSING_MODE,
		SSD1306_ADDRESSING_MODE,
		SSD1306_SET_COLUMN_ADDRESS,
		SSD1306_SET_LOWER_COL_ADDRESS,
		SSD1306_SET_HIGHER_COL_ADDRESS,
		SSD1306_SET_PAGE_ADDRESS,
		y/8,
		((y + desc->height)/8 - 1)
	};

Where

SSD1306_SET_LOWER_COL_ADDRESS = 0x20
SSD1306_SET_HIGHER_COL_ADDRESS = 0x5f

Also, the multiplex ratio in the device tree configuration should be set to height-1, so 31.

I am not sure where I am supposed to be able to set the "x" value in the ssd1306_write_default() function. This would allow me to configure the display without needing to modify the zephyr source files.