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Add reference to HX711 documentation to source

This commit is contained in:
Marcel Stör 2015-11-19 22:54:06 +01:00
parent c047d3445c
commit 6674a7d7f9
1 changed files with 7 additions and 4 deletions
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11
app/modules/hx711.c
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@ -1,3 +1,6 @@
// Module for HX711 load cell amplifier
// https://learn.sparkfun.com/tutorials/load-cell-amplifier-hx711-breakout-hookup-guide
#include "lualib.h" #include "lualib.h"
#include "lauxlib.h" #include "lauxlib.h"
#include "platform.h" #include "platform.h"
@ -32,7 +35,7 @@ static int ICACHE_FLASH_ATTR hx711_read(lua_State* L) {
//wakeup hx711 //wakeup hx711
platform_gpio_write(clk_pin,0); platform_gpio_write(clk_pin,0);
//wait for data ready. or time out. //wait for data ready. or time out.
//TODO: set pin inturrupt and come back to it. This may take up to 1/10 sec //TODO: set pin inturrupt and come back to it. This may take up to 1/10 sec
// or maybe just make an async version too and have both available. // or maybe just make an async version too and have both available.
@ -40,7 +43,7 @@ static int ICACHE_FLASH_ATTR hx711_read(lua_State* L) {
for (i = 0; i<HX711_MAX_WAIT && platform_gpio_read(data_pin)==1;i++){ for (i = 0; i<HX711_MAX_WAIT && platform_gpio_read(data_pin)==1;i++){
asm ("nop"); asm ("nop");
} }
//Handle timeout error //Handle timeout error
if (i>=HX711_MAX_WAIT) { if (i>=HX711_MAX_WAIT) {
return luaL_error( L, "ADC timeout!", ( unsigned )0 ); return luaL_error( L, "ADC timeout!", ( unsigned )0 );
@ -54,14 +57,14 @@ static int ICACHE_FLASH_ATTR hx711_read(lua_State* L) {
data = i==0 ? -1 : data|1; //signextend the first bit data = i==0 ? -1 : data|1; //signextend the first bit
} }
} }
//add 25th clock pulse to prevent protocol error (probably not needed //add 25th clock pulse to prevent protocol error (probably not needed
// since we'll go to sleep immediately after and reset on wakeup.) // since we'll go to sleep immediately after and reset on wakeup.)
platform_gpio_write(clk_pin,1); platform_gpio_write(clk_pin,1);
platform_gpio_write(clk_pin,0); platform_gpio_write(clk_pin,0);
//sleep //sleep
platform_gpio_write(clk_pin,1); platform_gpio_write(clk_pin,1);
lua_pushinteger( L, data ); lua_pushinteger( L, data );
return 1; return 1;
} }
#define MIN_OPT_LEVEL 2 #define MIN_OPT_LEVEL 2