How to wire LCD to Nordic Nrf5340 DK

[rohit-trustedwear]

I need help , I have flash ZS watch code to DK as per instruction for DK and then connected LCD using following configuration but I am only seeing backlight glowing and nothing appearing on LCD .The pins connections are as follows .
Nrf5340 DK ---> LCD
P0.18 QSPI_CS to CS
P0.17 QSPI_CLK to SPI CLK
PO.13 QSPI[0] to SPI MOSI
P0.14 QSPI[1] to SPI MISO
GPIO.0 25 to Reset
GPIO.0 7 to DC

And I have not connected pins for touch . Can you kindly check if something is wrong here . ?

[jakkra]

I assume you got it working, but the mappings are here anyway https://github.com/jakkra/ZSWatch/blob/main/app/boards/nrf5340dk_nrf5340_cpuapp.overlay#LL41C33-L41C33 check spi4, gc9a01, i2c_2 and
CST816S. Note you will only get 8MHz on the dk, as the pins for high speed spi are the button, and we need the buttons. So this will make the screen less responsive.

[rohit-trustedwear]

Thanks Sir .

[rohit-trustedwear]

Hi Sir , last time I closed because I saw my mistake in connection . But now I have connected as per your advice . But still I do not see lcd working . Can you please take a look at attached picture to find where I am wrong. It will be a great help.

[jakkra]

Yes because this fails

ZSWatch/app/drivers/kscan/kscan_cst816s.c

Line 249 in 8a71f5d

ret = i2c_reg_read_byte_dt(&cfg->i2c, CST816S_REG_CHIP_ID, &chip_id);

and it means it cannot communicate with the touch chip. Which means wiring or pin config is not correct most likely. Debug and make sure the overlay is picked up and thst really the pins in overlay are used for i2c.

[rohit-trustedwear]

Thanks . Found the exception is thrown and terminating the thread in line for CST816S_REG_IRQ_CTL. . I connected IRQ to TP_INT of touch screen .

[a-rivera-hidalgo]

Hi @rohit-trustedwear what did you connect TP_INT to? I seem to be having the same issue as you did and I still cannot get my touch screen to light up.

[felipe-lopezfolle]

Hi, @rohit-trustedwear, we seem to be in the same position as @a-rivera-hidalgo. We made the display work, but we failed to enable touch on the screen. We need to change any connections or something in the code?

[jakkra]

Hi, it really should be just a matter of choosing some suitable pins for the I2C, like I said before I don't have the display breakout with touch, hence have not tested it on the 5340dk. Also you could try swapping and use i2c3 instead of i2c2, could be worth a try. It's all set in this file:
https://github.com/jakkra/ZSWatch/blob/main/app/boards/nrf5340dk_nrf5340_cpuapp.overlay#L24

Or if someone can send me on PayPal the cost to buy this display etc. then I'll fix it.