108 lines
3.6 KiB
C
108 lines
3.6 KiB
C
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#include <stdlib.h>
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#include <string.h>
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#include "lauxlib.h"
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#include "module.h"
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#include "platform.h"
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#include "user_interface.h"
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#define NOP asm volatile(" nop \n\t")
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static inline void apa102_send_byte(uint32_t data_pin, uint32_t clock_pin, uint8_t byte) {
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int i;
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for (i = 0; i < 8; i++) {
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if (byte & 0x80) {
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GPIO_OUTPUT_SET(data_pin, PLATFORM_GPIO_HIGH); // Set pin high
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} else {
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GPIO_OUTPUT_SET(data_pin, PLATFORM_GPIO_LOW); // Set pin low
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}
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GPIO_OUTPUT_SET(clock_pin, PLATFORM_GPIO_HIGH); // Set pin high
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byte <<= 1;
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NOP;
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NOP;
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GPIO_OUTPUT_SET(clock_pin, PLATFORM_GPIO_LOW); // Set pin low
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NOP;
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NOP;
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}
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}
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static void apa102_send_buffer(uint32_t data_pin, uint32_t clock_pin, uint32_t *buf, uint32_t nbr_frames) {
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int i;
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// Send 32-bit Start Frame that's all 0x00
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apa102_send_byte(data_pin, clock_pin, 0x00);
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apa102_send_byte(data_pin, clock_pin, 0x00);
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apa102_send_byte(data_pin, clock_pin, 0x00);
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apa102_send_byte(data_pin, clock_pin, 0x00);
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// Send 32-bit LED Frames
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for (i = 0; i < nbr_frames; i++) {
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uint8_t *byte = (uint8_t *) buf++;
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// Set the first 3 bits of that byte to 1.
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// This makes the lua interface easier to use since you
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// don't have to worry about creating invalid LED Frames.
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byte[0] |= 0xE0;
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apa102_send_byte(data_pin, clock_pin, byte[0]);
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apa102_send_byte(data_pin, clock_pin, byte[1]);
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apa102_send_byte(data_pin, clock_pin, byte[2]);
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apa102_send_byte(data_pin, clock_pin, byte[3]);
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}
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// Send 32-bit End Frames
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uint32_t required_postamble_frames = (nbr_frames + 1) / 2;
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for (i = 0; i < required_postamble_frames; i++) {
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apa102_send_byte(data_pin, clock_pin, 0xFF);
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apa102_send_byte(data_pin, clock_pin, 0xFF);
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apa102_send_byte(data_pin, clock_pin, 0xFF);
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apa102_send_byte(data_pin, clock_pin, 0xFF);
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}
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}
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// Lua: apa102.write(data_pin, clock_pin, "string")
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// Byte quads in the string are interpreted as (brightness, B, G, R) values.
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// Only the first 5 bits of the brightness value is actually used (0-31).
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// This function does not corrupt your buffer.
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//
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// apa102.write(1, 3, string.char(31, 0, 255, 0)) uses GPIO5 for DATA and GPIO0 for CLOCK and sets the first LED green, with the brightness 31 (out of 0-32)
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// apa102.write(5, 6, string.char(255, 0, 0, 255):rep(10)) uses GPIO14 for DATA and GPIO12 for CLOCK and sets ten LED to red, with the brightness 31 (out of 0-32).
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// Brightness values are clamped to 0-31.
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static int apa102_write(lua_State* L) {
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uint8_t data_pin = luaL_checkinteger(L, 1);
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MOD_CHECK_ID(gpio, data_pin);
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uint32_t alt_data_pin = pin_num[data_pin];
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uint8_t clock_pin = luaL_checkinteger(L, 2);
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MOD_CHECK_ID(gpio, clock_pin);
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uint32_t alt_clock_pin = pin_num[clock_pin];
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size_t buf_len;
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const char *buf = luaL_checklstring(L, 3, &buf_len);
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uint32_t nbr_frames = buf_len / 4;
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if (nbr_frames > 100000) {
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return luaL_error(L, "The supplied buffer is too long, and might cause the callback watchdog to bark.");
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}
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// Initialize the output pins
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platform_gpio_mode(data_pin, PLATFORM_GPIO_OUTPUT, PLATFORM_GPIO_FLOAT);
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GPIO_OUTPUT_SET(alt_data_pin, PLATFORM_GPIO_HIGH); // Set pin high
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platform_gpio_mode(clock_pin, PLATFORM_GPIO_OUTPUT, PLATFORM_GPIO_FLOAT);
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GPIO_OUTPUT_SET(alt_clock_pin, PLATFORM_GPIO_LOW); // Set pin low
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// Send the buffers
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apa102_send_buffer(alt_data_pin, alt_clock_pin, (uint32_t *) buf, (uint32_t) nbr_frames);
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return 0;
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}
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LROT_BEGIN(apa102, NULL, 0)
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LROT_FUNCENTRY( write, apa102_write )
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LROT_END(apa102, NULL, 0)
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NODEMCU_MODULE(APA102, "apa102", apa102, NULL);
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