E-reader implementation.

1 files changed, 289 insertions, 0 deletions

diff --git a/main/epd.c b/main/epd.c
new file mode 100644
index 0000000..4b95b52
--- /dev/null
+++ b/main/epd.c
@@ -0,0 +1,289 @@
+#include <stdio.h>
+#include <string.h>
+
+#include <freertos/FreeRTOS.h>
+#include <freertos/task.h>
+
+#include <driver/spi_master.h>
+#include <driver/gpio.h>
+#include <esp_log.h>
+
+#include "epd.h"
+#include "util.h"
+
+#define EPD_SCREEN_WIDTH    800
+#define EPD_SCREEN_HEIGHT   480
+
+#define EPD_CS_PIN     GPIO_NUM_5
+#define EPD_DC_PIN     GPIO_NUM_15
+#define EPD_RST_PIN    GPIO_NUM_2
+#define EPD_CLK_PIN    GPIO_NUM_18
+#define EPD_MOSI_PIN   GPIO_NUM_23
+#define EPD_BUSY_PIN   GPIO_NUM_4
+
+static const char* TAG = "EPD";
+
+static spi_device_handle_t spi = NULL;
+
+static uint8_t VOLTAGE_FRAME[] = {
+	0x6, 0x3F, 0x3F, 0x11, 0x24, 0x7, 0x17,
+};
+
+static uint8_t LUT_VCOM[] = {	
+	0x0,	0xF,	0xF,	0x0,	0x0,	0x1,	
+	0x0,	0xF,	0x1,	0xF,	0x1,	0x2,	
+	0x0,	0xF,	0xF,	0x0,	0x0,	0x1,	
+	0x0,	0x0,	0x0,	0x0,	0x0,	0x0,	
+	0x0,	0x0,	0x0,	0x0,	0x0,	0x0,	
+	0x0,	0x0,	0x0,	0x0,	0x0,	0x0,	
+	0x0,	0x0,	0x0,	0x0,	0x0,	0x0,	
+};						
+
+static uint8_t LUT_WW[] = {	
+	0x10,	0xF,	0xF,	0x0,	0x0,	0x1,	
+	0x84,	0xF,	0x1,	0xF,	0x1,	0x2,	
+	0x20,	0xF,	0xF,	0x0,	0x0,	0x1,	
+	0x0,	0x0,	0x0,	0x0,	0x0,	0x0,	
+	0x0,	0x0,	0x0,	0x0,	0x0,	0x0,	
+	0x0,	0x0,	0x0,	0x0,	0x0,	0x0,	
+	0x0,	0x0,	0x0,	0x0,	0x0,	0x0,	
+};
+
+static uint8_t LUT_BW[] = {	
+	0x10,	0xF,	0xF,	0x0,	0x0,	0x1,	
+	0x84,	0xF,	0x1,	0xF,	0x1,	0x2,	
+	0x20,	0xF,	0xF,	0x0,	0x0,	0x1,	
+	0x0,	0x0,	0x0,	0x0,	0x0,	0x0,	
+	0x0,	0x0,	0x0,	0x0,	0x0,	0x0,	
+	0x0,	0x0,	0x0,	0x0,	0x0,	0x0,	
+	0x0,	0x0,	0x0,	0x0,	0x0,	0x0,	
+};
+
+static uint8_t LUT_WB[] = {	
+	0x80,	0xF,	0xF,	0x0,	0x0,	0x1,	
+	0x84,	0xF,	0x1,	0xF,	0x1,	0x2,	
+	0x40,	0xF,	0xF,	0x0,	0x0,	0x1,	
+	0x0,	0x0,	0x0,	0x0,	0x0,	0x0,	
+	0x0,	0x0,	0x0,	0x0,	0x0,	0x0,	
+	0x0,	0x0,	0x0,	0x0,	0x0,	0x0,	
+	0x0,	0x0,	0x0,	0x0,	0x0,	0x0,	
+};
+
+static uint8_t LUT_BB[] = {	
+	0x80,	0xF,	0xF,	0x0,	0x0,	0x1,	
+	0x84,	0xF,	0x1,	0xF,	0x1,	0x2,	
+	0x40,	0xF,	0xF,	0x0,	0x0,	0x1,	
+	0x0,	0x0,	0x0,	0x0,	0x0,	0x0,	
+	0x0,	0x0,	0x0,	0x0,	0x0,	0x0,	
+	0x0,	0x0,	0x0,	0x0,	0x0,	0x0,	
+	0x0,	0x0,	0x0,	0x0,	0x0,	0x0,	
+};
+
+static void spi_pre_cb_handler(spi_transaction_t *t)
+{
+	int dc = (int)t->user;
+	gpio_set_level(EPD_DC_PIN, dc);
+}
+
+static void send_cmd(uint8_t cmd)
+{
+	spi_transaction_t t;
+
+	memset(&t, 0, sizeof(t));	
+	t.length = 8;
+	t.tx_buffer = &cmd;
+	t.user = (void*)0; 
+	ESP_ERROR_CHECK(spi_device_polling_transmit(spi, &t));
+}
+
+static void send_data(uint8_t data)
+{
+	spi_transaction_t t;
+
+	memset(&t, 0, sizeof(t));	
+	t.length = 8;
+	t.tx_buffer = &data;
+	t.user = (void*)1; 
+	ESP_ERROR_CHECK(spi_device_polling_transmit(spi, &t));
+}
+
+static inline void wait_until_idle(void)
+{
+	int busy;
+
+	ESP_LOGI(TAG, "busy...");
+	do {
+		send_cmd(0x71);
+		busy = gpio_get_level(EPD_BUSY_PIN);
+	} while(busy == 0);
+	ESP_LOGI(TAG, "ready");
+	delay_ms(20);
+}
+
+static inline void reset(void)
+{
+	ESP_ERROR_CHECK(gpio_set_level(EPD_RST_PIN, 1));
+	delay_ms(200);
+	ESP_ERROR_CHECK(gpio_set_level(EPD_RST_PIN, 0));
+	delay_ms(2);
+	ESP_ERROR_CHECK(gpio_set_level(EPD_RST_PIN, 1));
+	delay_ms(200);
+}
+
+static inline void config_lut(uint8_t cmd, const uint8_t *lut)
+{
+	uint8_t i;
+
+	send_cmd(cmd);
+	for(i = 0; i < 42; i++)
+		send_data(lut[i]);
+}
+
+static inline void gpio_init(void)
+{
+	gpio_config_t io_cfg = {
+		.pin_bit_mask = ((1ULL << EPD_DC_PIN) | (1ULL << EPD_RST_PIN) | (1ULL << EPD_BUSY_PIN)),
+		.pull_up_en = true
+	};
+
+	ESP_ERROR_CHECK(gpio_config(&io_cfg));
+	ESP_ERROR_CHECK(gpio_set_direction(EPD_DC_PIN, GPIO_MODE_OUTPUT));
+	ESP_ERROR_CHECK(gpio_set_direction(EPD_RST_PIN, GPIO_MODE_OUTPUT));
+	ESP_ERROR_CHECK(gpio_set_direction(EPD_BUSY_PIN, GPIO_MODE_INPUT));
+}
+
+static void spi_init(void)
+{
+	spi_bus_config_t bus_cfg = {
+		.miso_io_num = -1,
+		.mosi_io_num = EPD_MOSI_PIN,
+		.sclk_io_num = EPD_CLK_PIN,
+		.quadwp_io_num = -1,
+		.quadhd_io_num = -1,
+		.max_transfer_sz = 8
+	};
+	ESP_ERROR_CHECK(spi_bus_initialize(SPI2_HOST, &bus_cfg, SPI_DMA_CH_AUTO));
+
+	spi_device_interface_config_t dev_cfg = {
+		.clock_speed_hz = 10 * 1000 * 1000,
+		.mode = 0,
+		.spics_io_num = EPD_CS_PIN,
+		.queue_size = 1,
+		.pre_cb = spi_pre_cb_handler
+	};
+	ESP_ERROR_CHECK(spi_bus_add_device(SPI2_HOST, &dev_cfg, &spi));
+}
+
+void epd_init(void)
+{
+	spi_init();
+	gpio_init();
+
+	reset();
+
+	send_cmd(0x01);
+	send_data(0x07);
+
+	send_data(*(VOLTAGE_FRAME + 6));
+	send_data(*(VOLTAGE_FRAME + 1));
+	send_data(*(VOLTAGE_FRAME + 2));
+	send_data(*(VOLTAGE_FRAME + 3));
+
+	send_cmd(0x82);
+	send_data(*(VOLTAGE_FRAME + 4));
+
+	send_cmd(0x06);
+	send_data(0x27);
+	send_data(0x27);
+	send_data(0x2F);
+	send_data(0x17);
+
+	send_cmd(0x30);
+	send_data(*(VOLTAGE_FRAME + 0));
+
+	send_cmd(0x04);
+	delay_ms(100);
+	wait_until_idle();	
+
+	send_cmd(0x00);
+	send_data(0x3F);
+
+	send_cmd(0x61);
+	send_data(0x03);
+	send_data(0x20);
+	send_data(0x01);
+	send_data(0xE0);
+
+	send_cmd(0x15);
+	send_data(0x00);
+
+	send_cmd(0x50);
+	send_data(0x10);
+	send_data(0x00);
+
+	send_cmd(0x60);
+	send_data(0x22);
+
+	send_cmd(0x65);
+	send_data(0x00);
+	send_data(0x00);
+	send_data(0x00);
+	send_data(0x00);
+
+	config_lut(0x20, LUT_VCOM);
+	config_lut(0x21, LUT_WW);
+	config_lut(0x22, LUT_BW);
+	config_lut(0x23, LUT_WB);
+	config_lut(0x24, LUT_BB);
+}
+
+static inline void refresh()
+{
+	send_cmd(0x12);
+	delay_ms(100);
+	wait_until_idle();
+}
+
+void epd_clear(void)
+{
+	uint16_t i, width, height;
+
+	width = (EPD_SCREEN_WIDTH % 8 == 0) ? (EPD_SCREEN_WIDTH / 8 ) : (EPD_SCREEN_WIDTH / 8 + 1);
+	height = EPD_SCREEN_HEIGHT;
+
+	send_cmd(0x10);
+	for(i = 0; i < height * width; i++)
+		send_data(0x00);
+
+	send_cmd(0x13);
+	for(i = 0; i < height * width; i++)
+		send_data(0x00);
+
+	refresh();
+}
+
+void epd_draw(const uint8_t pb[48000])
+{
+	uint32_t i, j, width, height;
+
+	width = (EPD_SCREEN_WIDTH % 8 == 0) ? (EPD_SCREEN_WIDTH / 8 ) : (EPD_SCREEN_WIDTH / 8 + 1);
+	height = EPD_SCREEN_HEIGHT;
+	
+	send_cmd(0x13);
+	for (i = 0; i < height; i++) {
+		for (j = 0; j < width; j++)
+			send_data(~pb[i * width + j]);
+	}
+
+	refresh();
+}
+
+void epd_sleep(void)
+{
+	send_cmd(0x02);
+	wait_until_idle();
+	send_cmd(0x07);
+	send_data(0xA5);
+}
+
+