338 lines
8.2 KiB
C
338 lines
8.2 KiB
C
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// Module for HX711 load cell amplifier
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// https://learn.sparkfun.com/tutorials/load-cell-amplifier-hx711-breakout-hookup-guide
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#include "module.h"
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#include "lauxlib.h"
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#include "lmem.h"
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#include "platform.h"
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#include <stdlib.h>
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#include <string.h>
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#include "user_interface.h"
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static uint8_t data_pin;
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static uint8_t clk_pin;
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// The fields below are after the pin_num conversion
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static uint8_t pin_data_pin;
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static uint8_t pin_clk_pin;
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#ifdef GPIO_INTERRUPT_ENABLE
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static platform_task_handle_t tasknumber;
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// HX711_STATUS can be defined to enable the hx711.status() function to get debug info
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#undef HX711_STATUS
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#define BUFFERS 2
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typedef struct {
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char *buf[BUFFERS];
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uint32_t dropped[BUFFERS];
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uint32_t timestamp[BUFFERS];
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uint32_t interrupts;
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uint32_t hx711_interrupts;
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uint16_t buflen;
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uint16_t used;
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uint32_t nobuffer;
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uint8_t active; // slot of the active buffer
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uint8_t freed; // slot of the most recently freed buffer
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uint8_t mode;
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uint8_t dropping; // is non zero when there is no space
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int cb_ref;
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} CONTROL;
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static CONTROL *control;
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#endif
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/*Lua: hx711.init(clk_pin,data_pin)*/
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static int hx711_init(lua_State* L) {
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clk_pin = luaL_checkint(L,1);
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data_pin = luaL_checkint(L,2);
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MOD_CHECK_ID( gpio, clk_pin );
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MOD_CHECK_ID( gpio, data_pin );
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platform_gpio_mode(clk_pin, PLATFORM_GPIO_OUTPUT, PLATFORM_GPIO_FLOAT);
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platform_gpio_mode(data_pin, PLATFORM_GPIO_INPUT, PLATFORM_GPIO_FLOAT);
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platform_gpio_write(clk_pin,1);//put chip to sleep.
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pin_data_pin = pin_num[data_pin];
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pin_clk_pin = pin_num[clk_pin];
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return 0;
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}
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static int32_t ICACHE_RAM_ATTR read_sample(char mode) {
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int i;
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int32_t data = 0;
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for (i = 0; i < 24 ; i++){ //clock in the 24 bits
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GPIO_REG_WRITE(GPIO_OUT_W1TS_ADDRESS, 1 << pin_clk_pin);
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GPIO_REG_WRITE(GPIO_OUT_W1TC_ADDRESS, 1 << pin_clk_pin);
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data = data << 1;
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if (GPIO_REG_READ(GPIO_IN_ADDRESS) & (1 << pin_data_pin)) {
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data = i == 0 ? -1 : data | 1; //signextend the first bit
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}
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}
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//add 25th-27th clock pulse to prevent protocol error
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for (i = 0; i <= mode; i++) {
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GPIO_REG_WRITE(GPIO_OUT_W1TS_ADDRESS, 1 << pin_clk_pin);
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GPIO_REG_WRITE(GPIO_OUT_W1TC_ADDRESS, 1 << pin_clk_pin);
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}
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return data;
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}
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#ifdef GPIO_INTERRUPT_ENABLE
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static void ICACHE_RAM_ATTR hx711_data_available() {
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if (!control) {
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return;
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}
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uint32_t bits = GPIO_REG_READ(GPIO_IN_ADDRESS);
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if (bits & (1 << pin_data_pin)) {
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return; // not ready
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}
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// Read a sample
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int32_t data = read_sample(control->mode);
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if (control->dropping) {
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if (control->active == control->freed) {
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// still can't advance
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control->nobuffer++;
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return;
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}
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// Advance
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control->active = (1 + control->active) % BUFFERS;
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control->dropping = 0;
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}
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// insert into the active buffer
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char *dest = control->buf[control->active] + control->used;
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*dest++ = data;
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*dest++ = data >> 8;
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*dest++ = data >> 16;
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control->used += 3;
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if (control->used == control->buflen) {
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control->used = 0;
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control->timestamp[control->active] = system_get_time();
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control->dropped[control->active] = control->nobuffer;
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control->nobuffer = 0;
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// post task
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platform_post_medium(tasknumber, control->active);
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uint8_t next_active = (1 + control->active) % BUFFERS;
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if (control->active == control->freed) {
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// We can't advance to the buffer
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control->dropping = 1;
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} else {
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// flip to other buffer
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control->active = next_active;
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}
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}
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}
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static uint32_t ICACHE_RAM_ATTR hx711_interrupt(uint32_t ret_gpio_status)
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{
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// This function really is running at interrupt level with everything
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// else masked off. It should take as little time as necessary.
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//
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//
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// This gets the set of pins which have changed status
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uint32 gpio_status = GPIO_REG_READ(GPIO_STATUS_ADDRESS);
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int pin_mask = 1 << pin_data_pin;
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int i;
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control->interrupts++;
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if (gpio_status & pin_mask) {
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uint32_t bits = GPIO_REG_READ(GPIO_IN_ADDRESS);
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control->hx711_interrupts++;
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if (!(bits & pin_mask)) {
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// is now ready to read
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hx711_data_available();
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}
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GPIO_REG_WRITE(GPIO_STATUS_W1TC_ADDRESS, gpio_status & pin_mask);
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}
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return gpio_status & ~pin_mask;
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}
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// Lua: hx711.start( mode, samples, callback )
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static int hx711_start( lua_State* L )
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{
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uint32_t mode = luaL_checkint( L, 1 );
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uint32_t samples = luaL_checkint( L, 2 );
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if (mode > 2) {
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return luaL_argerror( L, 1, "Mode value out of range" );
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}
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if (!samples || samples > 400) {
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return luaL_argerror( L, 2, "Samples value out of range (1-400)" );
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}
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if (control) {
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return luaL_error( L, "Already running" );
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}
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int buflen = 3 * samples;
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control = (CONTROL *) luaM_malloc(L, sizeof(CONTROL) + BUFFERS * buflen);
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if (!control) {
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return luaL_error( L, "Failed to allocate memory" );
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}
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int cb_ref;
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if (lua_type(L, 3) == LUA_TFUNCTION) {
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lua_pushvalue(L, 3); // copy argument (func) to the top of stack
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cb_ref = luaL_ref(L, LUA_REGISTRYINDEX);
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} else {
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luaM_free(L, control);
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control = NULL;
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return luaL_argerror( L, 3, "Not a callback function" );
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}
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memset(control, 0, sizeof(*control));
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control->buf[0] = (char *) (control + 1);
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control->buflen = buflen;
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int i;
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for (i = 1; i < BUFFERS; i++) {
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control->buf[i] = control->buf[i - 1] + buflen;
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}
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control->mode = mode;
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control->cb_ref = cb_ref;
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control->freed = BUFFERS - 1;
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// configure data_pin as interrupt input
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platform_gpio_register_intr_hook(1 << pin_data_pin, hx711_interrupt);
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platform_gpio_mode(data_pin, PLATFORM_GPIO_INT, PLATFORM_GPIO_FLOAT);
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platform_gpio_intr_init(data_pin, GPIO_PIN_INTR_NEGEDGE);
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// Wake up chip
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platform_gpio_write(clk_pin, 0);
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return 0;
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}
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// Lua: hx711.stop( )
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static int hx711_stop( lua_State* L )
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{
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if (control) {
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platform_gpio_mode(data_pin, PLATFORM_GPIO_INPUT, PLATFORM_GPIO_FLOAT);
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CONTROL *to_free = control;
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control = NULL;
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luaL_unref(L, LUA_REGISTRYINDEX, to_free->cb_ref);
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luaM_free(L, to_free);
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}
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return 0;
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}
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static int hx711_status( lua_State* L )
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{
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if (control) {
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lua_pushlstring(L, (char *) control, sizeof(*control));
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return 1;
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}
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return 0;
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}
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static void hx711_task(platform_task_param_t param, uint8_t prio)
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{
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(void) prio;
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if (!control) {
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return;
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}
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lua_State *L = lua_getstate();
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if (control->cb_ref != LUA_NOREF) {
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lua_rawgeti(L, LUA_REGISTRYINDEX, control->cb_ref);
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lua_pushlstring(L, control->buf[param], control->buflen);
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lua_pushinteger(L, control->timestamp[param]);
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lua_pushinteger(L, control->dropped[param]);
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control->freed = param;
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luaL_pcallx(L, 3, 0);
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}
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}
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#endif
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#define HX711_MAX_WAIT 1000000
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/*will only read chA@128gain*/
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/*Lua: result = hx711.read()*/
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static int hx711_read(lua_State* L) {
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int j;
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//TODO: double check init has happened first.
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//
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uint32_t mode = luaL_optinteger(L, 1, 0);
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if (mode > 2) {
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return luaL_argerror( L, 1, "Mode value out of range" );
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}
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#ifdef GPIO_INTERRUPT_ENABLE
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if (control) {
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hx711_stop(L);
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}
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#endif
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//wakeup hx711
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platform_gpio_write(clk_pin, 0);
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int32_t data;
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// read two samples if mode > 0. We discard the first read and return the
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// second value.
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for (j = (mode ? 1 : 0); j >= 0; j--) {
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uint32_t i;
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//wait for data ready. or time out.
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system_soft_wdt_feed(); //clear WDT... this may take a while.
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for (i = 0; i<HX711_MAX_WAIT && platform_gpio_read(data_pin)==1;i++){
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asm ("nop");
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}
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//Handle timeout error
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if (i >= HX711_MAX_WAIT) {
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return luaL_error( L, "ADC timeout!");
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}
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data = read_sample(mode);
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}
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//sleep -- unfortunately, this resets the mode to 0
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platform_gpio_write(clk_pin, 1);
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lua_pushinteger(L, data);
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return 1;
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}
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// Module function map
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LROT_BEGIN(hx711, NULL, 0)
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LROT_FUNCENTRY( init, hx711_init )
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LROT_FUNCENTRY( read, hx711_read )
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#ifdef GPIO_INTERRUPT_ENABLE
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LROT_FUNCENTRY( start, hx711_start )
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#ifdef HX711_STATUS
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LROT_FUNCENTRY( status, hx711_status )
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#endif
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LROT_FUNCENTRY( stop, hx711_stop )
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#endif
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LROT_END(hx711, NULL, 0)
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int luaopen_hx711(lua_State *L) {
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#ifdef GPIO_INTERRUPT_ENABLE
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tasknumber = platform_task_get_id(hx711_task);
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#endif
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return 0;
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}
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NODEMCU_MODULE(HX711, "hx711", hx711, luaopen_hx711);
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