SPI Master

[caetanowagner]

Hi all.
I think there is something I'm missing.
I'm using
macOS High Sierra version 10.13.6
Visual Studio Code version 1.59.1
ESP-IDF Extension version 1.1.1
ESP-IDF version 4.2.2
Python version 3.9.1
ESP32 chip revision: 1

I'm want esp32 to communicate to RA8875 (TFT display controller) via SPI 4 wires.
RA8875 datasheet shows SPI CPOL = high and CPHA = 1

I can initialise and add device to bus, here's the log
I (355) DisplayTFT: ... Initializing bus.
I (355) DisplayTFT: ... Adding device bus.

When I try to use

Code: [Select all] [Expand/Collapse]

1. ret = spi_device_transmit(spi, &t);

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got this
E (455) spi_master: check_trans_valid(661): invalid dev handle
I (455) DisplayTFT: LCD_CmdWrite ESP_ERR_INVALID_ARG

Here's the code

Code: [Select all] [Expand/Collapse]

1. //Pins definition
2. #define SPI_MISO 19     //SPI miso
3. #define SPI_MOSI 23     //SPI mosi
4. #define SPI_CLK 18      //SPI clock
5. #define SPI_CS 5        //SPI slave select
6.  
7. //SPI config
8. spi_bus_config_t bus_config;
9. memset(&bus_config, 0, sizeof(spi_bus_config_t));
10. bus_config.sclk_io_num = SPI_CLK;
11. bus_config.mosi_io_num = SPI_MOSI;
12. bus_config.miso_io_num =SPI_MISO;
13. bus_config.quadwp_io_num = -1; // Not used
14. bus_config.quadhd_io_num = -1; // Not used
15. bus_config.max_transfer_sz = 32;
16. ESP_LOGI(TAG, "... Initializing bus.");
17. ESP_ERROR_CHECK(spi_bus_initialize(HSPI_HOST, &bus_config, 1));
18.  
19. spi_device_handle_t handle;
20. spi_device_interface_config_t dev_config;
21. dev_config.address_bits = 0;
22. dev_config.command_bits = 0;
23. dev_config.dummy_bits = 0;
24. dev_config.mode = 3;
25. dev_config.duty_cycle_pos = 0;
26. dev_config.cs_ena_posttrans = 0;
27. dev_config.cs_ena_pretrans = 0;
28. dev_config.clock_speed_hz = 500000;    //500kHz
29. dev_config.spics_io_num = SPI_CS;
30. dev_config.queue_size = 1;
31. dev_config.pre_cb = NULL;
32. dev_config.post_cb = NULL;
33. ESP_LOGI(TAG, "... Adding device bus.");
34. ESP_ERROR_CHECK(spi_bus_add_device(HSPI_HOST, &dev_config, &handle));
35.  
36. void LCD_CmdWrite(spi_device_handle_t spi, const uint8_t addr, uint8_t val)
37. {
38.     esp_err_t ret;
39.     spi_transaction_t t;
40.     char data[3];
41.     char rx_data[3];
42.     data[0] = RA8875_Cmd_Write;
43.     data[1] = addr;
44.     data[2] = val;
45.  
46.     memset(&t, 0, sizeof(t));                   //Zero out the transaction
47.     t.addr = 0;
48.     t.cmd   = 0;
49.     t.flags     = 0;
50.     t.length    = 8 * 3; // Total data length, in bits NOT number of bytes.
51.     t.rxlength  = 0; // (0 defaults this to the value of ``length``)
52.     t.tx_buffer = &data;
53.     t.rx_buffer = &rx_data;
54.  
55.     ret = spi_device_transmit(spi, &t); //Transmit!
56.     if (ret != ESP_OK)
57.         ESP_LOGI(TAG, "LCD_CmdWrite %s", esp_err_to_name(ret));
58. }

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I tried to modify these variables

Code: [Select all] [Expand/Collapse]

1. t.addr  = 0;
2. t.cmd  = 0;
3. t.flags = 0;
4.  
5. dev_config.address_bits = 0;
6. dev_config.command_bits = 0;

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always unsuccessful.

I used this https://docs.espressif.com/projects/esp ... aster.html
and some other examples I found on the net.

Thanks.

[Victoria Nope]

If I were you and wanted to control such display in some reasonable way, I would, rather than crafting my own, focus on using some ready made graphics library such as LVGL. It is ported for ESP32 and supports your RA8875 controller.

[fasani]

I second Victoria recommendation here. I would also like to mention, that many SPI peripherals, need a reset before starting communication.
I checked the ra8875 in LVGL and has one, a part of a memory clear, maybe that's something you need to do additionally before sending your SPI commands.