Pi Pico 2040 and Waveshare 19907 ILI9488 - no output

[Stef1519]

Hi,

i have this Setup, and already successfully used this Display with "PicoMite" (an all in one Basic Interpreter for the Pico); Touch etc works fine there.

Pinout can be seen here:
https://www.welectron.com/Waveshare-19907-Pico-ResTouch-LCD-35

Now i switched over to the Arduino IDE, but i can´t get the Display to output anything.
The integrated SD Card Interface of this Display doesn´t share the SPI1 Interface of the Display, its running on SPI0, so no conflict can be possible.

I used the "A total of 2890 characters are drawn in each font then the time per character printed on screen"-example from TFT_eSPI, since i'm not quite familiar with c++ (can understand it, but don´t like to write it). I wanted to test it on a unmodified source basis, so i've chosen an example.

user_setup.h:
#define ILI9488_DRIVER
#define TFT_SPI_PORT 1
#define TFT_MISO 12
#define TFT_MOSI 11
#define TFT_SCLK 10
#define TFT_CS 9 // Chip select control pin
#define TFT_DC 8 // Data Command control pin
#define TFT_RST 15 // Reset pin (could connect to Arduino RESET pin)
#define TOUCH_CS 16 // Chip select pin (T_CS) of touch screen
#define SPI_FREQUENCY 27000000
#define SPI_TOUCH_FREQUENCY 2500000

Regardless which SPI Speed i used (tested down to 10 KHz) or trying to use the Ili9481-Driver (sort of compatible to the 9488, but wrong Color assignment), i get nothing on the display. My Oscilloscope shows activity on any assigned pin, but unless i hook up my Analyzer, i cannot validate the data sent over from the SPI1 Interface to the display.

BTW : I've already used the normal RPI Display Version (not this one, which is explicit for the Pico, the other Version has a Socket for the RPI 1-4) on other Platforms like AVR, 8051 and STM32F103 and even the Pico, all under Assembly language and as said, in this case also under PicoMite.

Any help is greatly appreciated!

Best regards
Stef

[Stef1519]

I have no clue whats going on. Hooked up my analyzer, compared the SPI capture to Init Sequence in ili9488_init.h, as well as the init sequence in

https://github.com/wa1tnr/PicoMite-tnr-a/blob/main/PicoMite/SPI-LCD.c

(its nearly the same sequence).

Also controlled LCD_cs and lcd_dc, its fine how it behaves.

Write sequence:

CMD 0x36, Data 0x48
CMD 0x36, Data 0x28
0x2a, Data 0x00,0x00,0x01,0xdf
0x2b, Data 0x00,0x00,0x01,0x3f
CMD 0x2c (write), data 0xf8,0xfc,0xf8,0xfa and so on....

[Stef1519]

Argh, in Picomite its defined as the ILI9488W and needs 16 Bits Transfers with a leading Zero for Writecommand and Writedata...as it looks by now. It initalized after modification of the sources of tft_espi, but i'm not sure if thats all what has to be done.

[Stef1519]

Works by using this Thread.

#1554

Hell, it would have save a lot of time and effort if i would have found that earlier. I still have wrong colors (wrong arrangement- i think RGB instead of GRB) , but than can be solved....