diff --git a/app/modules/ws2812.c b/app/modules/ws2812.c index 98cd23f1..7b751e66 100644 --- a/app/modules/ws2812.c +++ b/app/modules/ws2812.c @@ -4,54 +4,46 @@ #include "c_stdlib.h" #include "c_string.h" #include "user_interface.h" +#include "driver/uart.h" -static inline uint32_t _getCycleCount(void) { - uint32_t cycles; - __asm__ __volatile__("rsr %0,ccount":"=a" (cycles)); - return cycles; -} - -// This algorithm reads the cpu clock cycles to calculate the correct -// pulse widths. It works in both 80 and 160 MHz mode. -// The values for t0h, t1h, ttot have been tweaked and it doesn't get faster than this. -// The datasheet is confusing and one might think that a shorter pulse time can be achieved. -// The period has to be at least 1.25us, even if the datasheet says: -// T0H: 0.35 (+- 0.15) + T0L: 0.8 (+- 0.15), which is 0.85<->1.45 us. -// T1H: 0.70 (+- 0.15) + T1L: 0.6 (+- 0.15), which is 1.00<->1.60 us. -// Anything lower than 1.25us will glitch in the long run. +// Stream data using UART1 routed to GPIO2 +// NODE_DEBUG should not be activated because it also uses UART1 static void ICACHE_RAM_ATTR ws2812_write(uint8_t pin, uint8_t *pixels, uint32_t length) { - uint8_t *p, *end, pixel, mask; - uint32_t t, t0h, t1h, ttot, c, start_time, pin_mask; - pin_mask = 1 << pin; - p = pixels; - end = p + length; - pixel = *p++; - mask = 0x80; - start_time = 0; - t0h = (1000 * system_get_cpu_freq()) / 3022; // 0.35us (spec=0.35 +- 0.15) - t1h = (1000 * system_get_cpu_freq()) / 1477; // 0.70us (spec=0.70 +- 0.15) - ttot = (1000 * system_get_cpu_freq()) / 800; // 1.25us (MUST be >= 1.25) + // Data are sent LSB first, with a start bit at 0, an end bit at 1 and all inverted + // 0b00110111 => 110111 => [0]111011[1] => 10001000 => 00 + // 0b00000111 => 000111 => [0]111000[1] => 10001110 => 01 + // 0b00110100 => 110100 => [0]001011[1] => 11101000 => 10 + // 0b00000100 => 000100 => [0]001000[1] => 11101110 => 11 + uint8_t _uartData[4] = { 0b00110111, 0b00000111, 0b00110100, 0b00000100 }; - while (true) { - if (pixel & mask) { - t = t1h; - } else { - t = t0h; - } - while (((c = _getCycleCount()) - start_time) < ttot); // Wait for the previous bit to finish - GPIO_REG_WRITE(GPIO_OUT_W1TS_ADDRESS, pin_mask); // Set pin high - start_time = c; // Save the start time - while (((c = _getCycleCount()) - start_time) < t); // Wait for high time to finish - GPIO_REG_WRITE(GPIO_OUT_W1TC_ADDRESS, pin_mask); // Set pin low - if (!(mask >>= 1)) { // Next bit/byte - if (p >= end) { - break; - } - pixel= *p++; - mask = 0x80; - } - } + // Configure UART1 + // Set baudrate of UART1 to 3200000 + WRITE_PERI_REG(UART_CLKDIV(1), UART_CLK_FREQ / 3200000); + // Set UART Configuration No parity / 6 DataBits / 1 StopBits / Invert TX + WRITE_PERI_REG(UART_CONF0(1), UART_TXD_INV | (1 << UART_STOP_BIT_NUM_S) | (1 << UART_BIT_NUM_S)); + + // Redirect UART1 to GPIO2 + // Disable GPIO2 + GPIO_REG_WRITE(GPIO_ENABLE_W1TC_ADDRESS, BIT2); + // Enable Function 2 for GPIO2 (U1TXD) + PIN_FUNC_SELECT(PERIPHS_IO_MUX_GPIO2_U, FUNC_U1TXD_BK); + + uint8_t *end = pixels + length; + do { + uint8_t value = *pixels++; + + // Wait enough space in the FIFO buffer + // (Less than 124 bytes in the buffer) + while (((READ_PERI_REG(UART_STATUS(1)) >> UART_TXFIFO_CNT_S) & UART_TXFIFO_CNT) > 124); + + // Fill the buffer + WRITE_PERI_REG(UART_FIFO(1), _uartData[(value >> 6) & 3]); + WRITE_PERI_REG(UART_FIFO(1), _uartData[(value >> 4) & 3]); + WRITE_PERI_REG(UART_FIFO(1), _uartData[(value >> 2) & 3]); + WRITE_PERI_REG(UART_FIFO(1), _uartData[(value >> 0) & 3]); + + } while(pixels < end); } // Lua: ws2812.writergb(pin, "string") @@ -87,14 +79,8 @@ static int ICACHE_FLASH_ATTR ws2812_writergb(lua_State* L) buffer[i + 1] = r; } - // Initialize the output pin and wait a bit - platform_gpio_mode(pin, PLATFORM_GPIO_OUTPUT, PLATFORM_GPIO_FLOAT); - platform_gpio_write(pin, 0); - // Send the buffer - ets_intr_lock(); ws2812_write(pin_num[pin], (uint8_t*) buffer, length); - ets_intr_unlock(); c_free(buffer); @@ -113,14 +99,8 @@ static int ICACHE_FLASH_ATTR ws2812_writegrb(lua_State* L) { size_t length; const char *buffer = luaL_checklstring(L, 2, &length); - // Initialize the output pin - platform_gpio_mode(pin, PLATFORM_GPIO_OUTPUT, PLATFORM_GPIO_FLOAT); - platform_gpio_write(pin, 0); - // Send the buffer - ets_intr_lock(); ws2812_write(pin_num[pin], (uint8_t*) buffer, length); - ets_intr_unlock(); return 0; }