ILI9341 read registers in ESP-IDF

[noiseman]

Hi ALL,

In my app for some purposes I need not only to draw on TFT but also read some registers of ILI9341. There is an example in ESP-IDF which demonstartes of how to use ILI9341: https://github.com/espressif/esp-idf/tr ... spi_master In this example there is a function to Read Display Identification Information:

Code: [Select all] [Expand/Collapse]

1. uint32_t lcd_get_id(spi_device_handle_t spi)
2. {
3.     //get_id cmd
4.     lcd_cmd(spi, 0x04);
5.  
6.     spi_transaction_t t;
7.     memset(&t, 0, sizeof(t));
8.     t.length=8*3;
9.     t.flags = SPI_TRANS_USE_RXDATA;
10.     t.user = (void*)1;
11.  
12.     esp_err_t ret = spi_device_polling_transmit(spi, &t);
13.     assert( ret == ESP_OK );
14.  
15.     return *(uint32_t*)t.rx_data;
16. }

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but it always returns zeros and thats OK, but if I change port for example to 0x0A (Read Display Power Mode) it also always returns zeros....

I tried to test my hardware with Arduino and it works excellent:

Code: [Select all] [Expand/Collapse]

1. #include "SPI.h"
2. #include "Adafruit_GFX.h"
3. #include "Adafruit_ILI9341.h"
4.  
5. #define TFT_CS   27
6. #define TFT_DC   18
7. #define TFT_MOSI 15
8. #define TFT_CLK  14
9. #define TFT_RST  25
10. #define TFT_MISO 2
11. #define TFT_LED   26  // GPIO not managed by library
12.  
13. Adafruit_ILI9341 tft = Adafruit_ILI9341(TFT_CS, TFT_DC, TFT_MOSI, TFT_CLK, TFT_RST, TFT_MISO);
14.  
15. void setup() {
16.   Serial.begin(115200);
17.   Serial.println("ILI9341 Test!");
18.  
19.   tft.begin();
20.   pinMode(TFT_LED, OUTPUT);
21.  
22.   uint8_t x = tft.readcommand8(ILI9341_RDMODE, 0);
23.   Serial.print("Display Power Mode: 0x"); Serial.println(x, HEX);
24.   x = tft.readcommand8(ILI9341_RDMADCTL, 0);
25.   Serial.print("MADCTL Mode: 0x"); Serial.println(x, HEX);
26.   x = tft.readcommand8(ILI9341_RDPIXFMT, 0);
27.   Serial.print("Pixel Format: 0x"); Serial.println(x, HEX);
28.   x = tft.readcommand8(ILI9341_RDIMGFMT, 0);
29.   Serial.print("Image Format: 0x"); Serial.println(x, HEX);
30.   x = tft.readcommand8(ILI9341_RDSELFDIAG, 0);
31.   Serial.print("Self Diagnostic: 0x"); Serial.println(x, HEX);
32.   x = tft.readcommand8(ILI9341_RDDID, 0);
33.   Serial.print("Identification information: 0x"); Serial.println(x, HEX);
34. }
35.  
36. void loop(void){}

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Using this code I'm finally got registers:

Code: [Select all] [Expand/Collapse]

1. 10:02:17.198 -> load:0x3fff001c,len:1216
2. 10:02:17.198 -> ho 0 tail 12 room 4
3. 10:02:17.198 -> load:0x40078000,len:9720
4. 10:02:17.198 -> ho 0 tail 12 room 4
5. 10:02:17.198 -> load:0x40080400,len:6364
6. 10:02:17.198 -> entry 0x400806b8
7. 10:02:17.367 -> ILI9341 Test!
8. 10:02:18.084 -> Display Power Mode: 0x94
9. 10:02:18.084 -> MADCTL Mode: 0x48
10. 10:02:18.084 -> Pixel Format: 0x5
11. 10:02:18.084 -> Image Format: 0x80
12. 10:02:18.084 -> Self Diagnostic: 0xC0
13. 10:02:18.084 -> Identification information: 0x0

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In Arduino libs reading registers realized the following way:

Code: [Select all] [Expand/Collapse]

1.  
2. uint8_t Adafruit_ILI9341::readcommand8(uint8_t commandByte, uint8_t index) {
3.   uint8_t data = 0x10 + index;
4.   Adafruit_SPITFT::sendCommand(0xD9, &data, 1); // Set Index Register
5.   return Adafruit_SPITFT::readcommand8(commandByte);
6. }
7.  
8. void Adafruit_SPITFT::sendCommand(uint8_t commandByte, uint8_t *dataBytes,
9.                                   uint8_t numDataBytes) {
10.   SPI_BEGIN_TRANSACTION();
11.   if (_cs >= 0)
12.     SPI_CS_LOW();
13.  
14.   SPI_DC_LOW();          // Command mode
15.   spiWrite(commandByte); // Send the command byte
16.  
17.   SPI_DC_HIGH();
18.   for (int i = 0; i < numDataBytes; i++) {
19.     spiWrite(*dataBytes); // Send the data bytes
20.     dataBytes++;
21.     if ((connection == TFT_PARALLEL) && tft8.wide) {
22.       SPI_WRITE16(*(uint16_t *)dataBytes);
23.       dataBytes += 2;
24.     } else {
25.       spiWrite(*dataBytes); // Send the data bytes
26.       dataBytes++;
27.     }
28.   }
29.  
30.   if (_cs >= 0)
31.     SPI_CS_HIGH();
32.   SPI_END_TRANSACTION();
33. }
34.  
35. uint8_t Adafruit_SPITFT::readcommand8(uint8_t commandByte, uint8_t index) {
36.   uint8_t result;
37.   startWrite();
38.   SPI_DC_LOW(); // Command mode
39.   spiWrite(commandByte);
40.   SPI_DC_HIGH(); // Data mode
41.   do {
42.     result = spiRead();
43.   } while (index--); // Discard bytes up to index'th
44.   endWrite();
45.   return result;
46. }

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So the question is: How to read ILI9341 registers using ESP-IDF SPI API?

Thanks in advance!

[SinglWolf]

The situation is similar with the display on ILI9488. Please clarify this issue.