pimoroni-pico/drivers/st7735/st7735.cpp

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#include "st7735.hpp"
#include <cstdlib>
#include <math.h>
#include "hardware/dma.h"
#include "hardware/pwm.h"
namespace pimoroni {
enum reg : uint8_t {
SWRESET = 0x01,
RDDID = 0x04,
RDDRST = 0x09,
RDDPM = 0x0A,
RDDMADCTL = 0x0B,
RDDCOLMOD = 0x0C,
RDDIM = 0x0D,
RDDSM = 0x0E,
RDDSDR = 0x0F,
SLPIN = 0x10,
SLPOUT = 0x11,
PTLON = 0x12,
NORON = 0x13,
INVOFF = 0x20,
INVON = 0x21,
GAMSET = 0x26,
DISPOFF = 0x28,
DISPON = 0x29,
CASET = 0x2A,
RASET = 0x2B,
RAMWR = 0x2C,
RGBSET = 0x2D,
RAMRD = 0x2E,
PTLAR = 0x30,
SCRLAR = 0x33,
TEOFF = 0x34,
TEON = 0x35,
MADCTL = 0x36, // Memory Data Access Control
VSCSAD = 0x37,
IDMOFF = 0x38, // Idle Mode Off
IDMON = 0x39, // Idle Mode On
COLMOD = 0x3A,
FRMCTR1 = 0xB1,
FRMCTR2 = 0xB2,
FRMCTR3 = 0xB3,
INVCTR = 0xB4,
DISSET5 = 0xB6,
PWCTR1 = 0xC0,
PWCTR2 = 0xC1,
PWCTR3 = 0xC2,
PWCTR4 = 0xC3,
PWCTR5 = 0xC4,
VMCTR1 = 0xC5,
RDID1 = 0xDA,
RDID2 = 0xDB,
RDID3 = 0xDC,
RDID4 = 0xDD,
GMCTRP1 = 0xE0,
GMCTRN1 = 0xE1,
PWMTR6 = 0xFC
};
void ST7735::init(bool auto_init_sequence) {
// configure spi interface and pins
spi_init(spi, spi_baud);
gpio_set_function(dc, GPIO_FUNC_SIO);
gpio_set_dir(dc, GPIO_OUT);
gpio_set_function(cs, GPIO_FUNC_SIO);
gpio_set_dir(cs, GPIO_OUT);
gpio_set_function(sck, GPIO_FUNC_SPI);
gpio_set_function(mosi, GPIO_FUNC_SPI);
if(miso != PIN_UNUSED) {
gpio_set_function(miso, GPIO_FUNC_SPI);
}
// if supported by the display then the vsync pin is
// toggled high during vertical blanking period
if(vsync != PIN_UNUSED) {
gpio_set_function(vsync, GPIO_FUNC_SIO);
gpio_set_dir(vsync, GPIO_IN);
gpio_set_pulls(vsync, false, true);
}
// if a backlight pin is provided then set it up for
// pwm control
if(bl != PIN_UNUSED) {
pwm_config cfg = pwm_get_default_config();
pwm_set_wrap(pwm_gpio_to_slice_num(bl), 65535);
pwm_init(pwm_gpio_to_slice_num(bl), &cfg, true);
gpio_set_function(bl, GPIO_FUNC_PWM);
}
// if auto_init_sequence then send initialisation sequence
// for our standard displays based on the width and height
if(auto_init_sequence) {
command(reg::SWRESET);
sleep_ms(150);
command(reg::SLPOUT);
sleep_ms(500);
command(reg::FRMCTR1, 3, "\x01\x2c\x2d"); // Rate = fosc/(1x2+40) * (LINE+2C+2D)
command(reg::FRMCTR2, 3, "\x01\x2c\x2d"); // Rate = fosc/(1x2+40) * (LINE+2C+2D)
command(reg::FRMCTR3, 6, "\x01\x2c\x2d\x01\x2c\x2d"); // Rate = fosc/(1x2+40) * (LINE+2C+2D)
command(reg::INVCTR, 1, "\x07");
command(reg::PWCTR1, 3, "\xa2\x02\x84");
command(reg::PWCTR2, 2, "\x0a\x00");
command(reg::PWCTR4, 2, "\x8a\x2a");
command(reg::PWCTR5, 2, "\x8a\xee");
command(reg::VMCTR1, 1, "\x0e");
// if invert
// command(reg::INVON)
// else
command(reg::INVON);
command(reg::MADCTL, 1, "\x68"); // 0b0110 1000 (0x68)
command(reg::COLMOD, 1, "\x05");
offset_cols = (ROWS - width) / 2;
offset_rows = (COLS - height) / 2;
char buf[4];
buf[0] = 0;
buf[1] = offset_cols;
buf[2] = 0;
buf[3] = width + offset_cols - 1;
command(reg::CASET, 4, buf);
buf[1] = offset_rows;
buf[3] = height + offset_rows - 1;
command(reg::RASET, 4, buf);
command(reg::GMCTRP1, 16, "\x02\x1c\x07\x12\x37\x32\x29\x2d\x29\x25\x2b\x39\x00\x01\x03\x10");
command(reg::GMCTRN1, 16, "\x03\x1d\x07\x06\x2e\x2c\x29\x2d\x2e\x2e\x37\x3f\x00\x00\x02\x10");
command(reg::NORON);
sleep_ms(100);
command(reg::DISPON);
sleep_ms(100);
}
}
spi_inst_t* ST7735::get_spi() const {
return spi;
}
int ST7735::get_cs() const {
return cs;
}
int ST7735::get_dc() const {
return dc;
}
int ST7735::get_sck() const {
return sck;
}
int ST7735::get_mosi() const {
return mosi;
}
int ST7735::get_bl() const {
return bl;
}
void ST7735::command(uint8_t command, size_t len, const char *data) {
gpio_put(cs, 0);
gpio_put(dc, 0); // command mode
spi_write_blocking(spi, &command, 1);
if(data) {
gpio_put(dc, 1); // data mode
spi_write_blocking(spi, (const uint8_t*)data, len);
}
gpio_put(cs, 1);
}
// Native 16-bit framebuffer update
void ST7735::update() {
command(reg::RAMWR, width * height * sizeof(uint16_t), (const char*)frame_buffer);
}
// 8-bit framebuffer with palette conversion update
void ST7735::update(uint16_t *palette) {
command(reg::RAMWR);
uint16_t row[width];
gpio_put(dc, 1); // data mode
gpio_put(cs, 0);
for(auto y = 0u; y < height; y++) {
for(auto x = 0u; x < width; x++) {
auto i = y * width + x;
row[x] = palette[((uint8_t *)frame_buffer)[i]];
}
// TODO: Add DMA->SPI / PIO while we prep the next row
spi_write_blocking(spi, (const uint8_t*)row, width * sizeof(uint16_t));
}
gpio_put(cs, 1);
}
void ST7735::set_backlight(uint8_t brightness) {
// gamma correct the provided 0-255 brightness value onto a
// 0-65535 range for the pwm counter
float gamma = 2.8;
uint16_t value = (uint16_t)(pow((float)(brightness) / 255.0f, gamma) * 65535.0f + 0.5f);
pwm_set_gpio_level(bl, value);
}
}