I'm trying to use this display http://www.elstore.it/wp-content/upload ... 64BKWT.pdf with an esp32. It has a NT7534 controller.
I want to connect it via SPI interface to an ESP32 DevKitC, using the esp-idf.
Initially I tried using the U8g2 library with the
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u8g2_Setup_nt7534_tg12864r_fThe display initialization procedure should be really simple, and after that I simply flush in some lines to see if anything appears, but the screen is always unresponsive.
The screen is connected to my ESP32 (through a breakboard) in the following way:
CS -> IO22
DC(RS) -> IO21
RESET -> IO18
R/W -> GROUND
E -> GROUND
D0...D5 -> GROUND
MOSI -> IO23
CLK -> IO19
P/S -> GROUND
I have also added the necessary external capacitors. I checked all the lines with the oscilloscope and everything seems to be working properly (clean signals, correct timings,...). Assuming that my hardware configuration is correct, could someone take a look at my code and tell me if I'm doing anything wrong?
my main.c:
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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_system.h"
#include "driver/spi_master.h"
#include "soc/gpio_struct.h"
#include "driver/gpio.h"
#include "esp_log.h"
//#define PIN_NUM_MISO 25
#define PIN_NUM_MOSI 23
#define PIN_NUM_CLK 19
#define PIN_NUM_CS 22
#define PIN_NUM_DC 21
#define PIN_NUM_RST 18
//#define PIN_NUM_BCKL 5
#define TAG "MainApp"
/* The commands on the serial line are taken by the NT7534 in reversed order
(D7 through D0) */
uint8_t reverse_byte(uint8_t x)
{
static const uint8_t table[] = {
0x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0,
0x10, 0x90, 0x50, 0xd0, 0x30, 0xb0, 0x70, 0xf0,
0x08, 0x88, 0x48, 0xc8, 0x28, 0xa8, 0x68, 0xe8,
0x18, 0x98, 0x58, 0xd8, 0x38, 0xb8, 0x78, 0xf8,
0x04, 0x84, 0x44, 0xc4, 0x24, 0xa4, 0x64, 0xe4,
0x14, 0x94, 0x54, 0xd4, 0x34, 0xb4, 0x74, 0xf4,
0x0c, 0x8c, 0x4c, 0xcc, 0x2c, 0xac, 0x6c, 0xec,
0x1c, 0x9c, 0x5c, 0xdc, 0x3c, 0xbc, 0x7c, 0xfc,
0x02, 0x82, 0x42, 0xc2, 0x22, 0xa2, 0x62, 0xe2,
0x12, 0x92, 0x52, 0xd2, 0x32, 0xb2, 0x72, 0xf2,
0x0a, 0x8a, 0x4a, 0xca, 0x2a, 0xaa, 0x6a, 0xea,
0x1a, 0x9a, 0x5a, 0xda, 0x3a, 0xba, 0x7a, 0xfa,
0x06, 0x86, 0x46, 0xc6, 0x26, 0xa6, 0x66, 0xe6,
0x16, 0x96, 0x56, 0xd6, 0x36, 0xb6, 0x76, 0xf6,
0x0e, 0x8e, 0x4e, 0xce, 0x2e, 0xae, 0x6e, 0xee,
0x1e, 0x9e, 0x5e, 0xde, 0x3e, 0xbe, 0x7e, 0xfe,
0x01, 0x81, 0x41, 0xc1, 0x21, 0xa1, 0x61, 0xe1,
0x11, 0x91, 0x51, 0xd1, 0x31, 0xb1, 0x71, 0xf1,
0x09, 0x89, 0x49, 0xc9, 0x29, 0xa9, 0x69, 0xe9,
0x19, 0x99, 0x59, 0xd9, 0x39, 0xb9, 0x79, 0xf9,
0x05, 0x85, 0x45, 0xc5, 0x25, 0xa5, 0x65, 0xe5,
0x15, 0x95, 0x55, 0xd5, 0x35, 0xb5, 0x75, 0xf5,
0x0d, 0x8d, 0x4d, 0xcd, 0x2d, 0xad, 0x6d, 0xed,
0x1d, 0x9d, 0x5d, 0xdd, 0x3d, 0xbd, 0x7d, 0xfd,
0x03, 0x83, 0x43, 0xc3, 0x23, 0xa3, 0x63, 0xe3,
0x13, 0x93, 0x53, 0xd3, 0x33, 0xb3, 0x73, 0xf3,
0x0b, 0x8b, 0x4b, 0xcb, 0x2b, 0xab, 0x6b, 0xeb,
0x1b, 0x9b, 0x5b, 0xdb, 0x3b, 0xbb, 0x7b, 0xfb,
0x07, 0x87, 0x47, 0xc7, 0x27, 0xa7, 0x67, 0xe7,
0x17, 0x97, 0x57, 0xd7, 0x37, 0xb7, 0x77, 0xf7,
0x0f, 0x8f, 0x4f, 0xcf, 0x2f, 0xaf, 0x6f, 0xef,
0x1f, 0x9f, 0x5f, 0xdf, 0x3f, 0xbf, 0x7f, 0xff,
};
return table[x];
}
//Send a command to the LCD. Uses spi_device_transmit, which waits until the transfer is complete.
void lcd_cmd(spi_device_handle_t spi, const uint8_t cmd)
{
esp_err_t ret;
spi_transaction_t t;
const uint8_t reversed = reverse_byte(cmd);
memset(&t, 0, sizeof(t)); //Zero out the transaction
t.length = 8; //Command is 8 bits
t.tx_buffer = &reversed; //The data is the cmd itself
t.user = (void *)0; //D/C needs to be set to 0
ret = spi_device_transmit(spi, &t); //Transmit!
assert(ret == ESP_OK); //Should have had no issues.
}
//Send data to the LCD. Uses spi_device_transmit, which waits until the transfer is complete.
void lcd_data(spi_device_handle_t spi, const uint8_t *data, int len)
{
esp_err_t ret;
spi_transaction_t t;
if (len == 0)
return; //no need to send anything
memset(&t, 0, sizeof(t)); //Zero out the transaction
t.length = len * 8; //Len is in bytes, transaction length is in bits.
t.tx_buffer = data; //Data
t.user = (void *)1; //D/C needs to be set to 1
ret = spi_device_transmit(spi, &t); //Transmit!
assert(ret == ESP_OK); //Should have had no issues.
}
//This function is called (in irq context!) just before a transmission starts. It will
//set the D/C line to the value indicated in the user field.
void lcd_spi_pre_transfer_callback(spi_transaction_t *t)
{
int dc = (int)t->user;
gpio_set_level(PIN_NUM_DC, dc);
}
//Initialize the display
void lcd_init(spi_device_handle_t spi)
{
//Initialize non-SPI GPIOs
gpio_set_direction(PIN_NUM_DC, GPIO_MODE_OUTPUT);
gpio_set_direction(PIN_NUM_RST, GPIO_MODE_OUTPUT);
//Reset the display
gpio_set_level(PIN_NUM_RST, 0);
vTaskDelay(100 / portTICK_RATE_MS);
gpio_set_level(PIN_NUM_RST, 1);
vTaskDelay(100 / portTICK_RATE_MS);
lcd_cmd(spi, 0xA2); // bias
lcd_cmd(spi, 0xA0); // ADC
lcd_cmd(spi, 0xCF); // COM reverse
lcd_cmd(spi, 0x24); // resistor ratio
lcd_cmd(spi, 0x81); // electronic volume
lcd_cmd(spi, 0x1A); // contrast
lcd_cmd(spi, 0x2F); // power control
lcd_cmd(spi, 0xAF); // display on
}
void app_main()
{
esp_err_t ret;
uint8_t data;
spi_device_handle_t spi;
spi_bus_config_t buscfg;
memset(&buscfg, 0, sizeof(spi_bus_config_t));
buscfg.miso_io_num = -1;
buscfg.mosi_io_num = PIN_NUM_MOSI;
buscfg.sclk_io_num = PIN_NUM_CLK;
buscfg.quadwp_io_num = -1;
buscfg.quadhd_io_num = -1;
//.max_transfer_sz=PARALLEL_LINES*320*2+8;
buscfg.flags = (SPICOMMON_BUSFLAG_SCLK | SPICOMMON_BUSFLAG_MOSI);
spi_device_interface_config_t devcfg = {
#ifdef CONFIG_LCD_OVERCLOCK
.clock_speed_hz = 26 * 1000 * 1000, //Clock out at 26 MHz
#else
.clock_speed_hz = 10 * 1000, //Clock out at 10 KHz
#endif
.mode = 0, //SPI mode 0
.spics_io_num = PIN_NUM_CS, //CS pin
.queue_size = 7, //We want to be able to queue 7 transactions at a time
.pre_cb=lcd_spi_pre_transfer_callback, //Specify pre-transfer callback to handle D/C line
};
//Initialize the SPI bus
ret = spi_bus_initialize(HSPI_HOST, &buscfg, 1);
ESP_ERROR_CHECK(ret);
ESP_LOGI(TAG, "Init spi");
//Attach the LCD to the SPI bus
ret = spi_bus_add_device(HSPI_HOST, &devcfg, &spi);
ESP_ERROR_CHECK(ret);
ESP_LOGI(TAG, "Init device");
//Initialize the LCD
lcd_init(spi);
//Initialize the effect displayed
ESP_ERROR_CHECK(ret);
//Go do nice stuff.
data = 0x0F;
while(1){
for (uint8_t i = 0; i < 8; i++)
{
/* start from the first column */
lcd_cmd(spi, 0x10);
lcd_cmd(spi, 0x00);
/* cycle 8 pages */
lcd_cmd(spi, (0xB0|i));
for (int j = 0; j < 128; j++)
{
/* always send 0x0F - I expect some stripes on the screen */
lcd_data(spi, &data, 1);
}
}
vTaskDelay(1 / portTICK_RATE_MS);
}
}