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fix for ds18b20 negative decimals 

ds18b20 decimals do not take into account the sign bit. Since the original calculation was not so readable, rewritten in readable way that also fixes the bug. Same code as PR against master.
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petur 2018-03-25 22:56:01 +02:00 committed by GitHub
parent 519d6df62c
commit a1e02fc6a8
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 4 additions and 2 deletions
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6
app/modules/ds18b20.c
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@ -192,6 +192,7 @@ static int ds18b20_lua_read(lua_State *L) {
static int ds18b20_read_device(uint8_t *ds18b20_device_rom) {
lua_State *L = lua_getstate();
int16_t ds18b20_raw_temp;
if (onewire_crc8(ds18b20_device_rom,7) == ds18b20_device_rom[7]) {
@ -216,8 +217,9 @@ static int ds18b20_read_device(uint8_t *ds18b20_device_rom) {
lua_pushfstring(L, "%d:%d:%d:%d:%d:%d:%d:%d", ds18b20_device_rom[0], ds18b20_device_rom[1], ds18b20_device_rom[2], ds18b20_device_rom[3], ds18b20_device_rom[4], ds18b20_device_rom[5], ds18b20_device_rom[6], ds18b20_device_rom[7]);
ds18b20_device_scratchpad_conf = (ds18b20_device_scratchpad[4] >> 5) + 9;
ds18b20_device_scratchpad_temp = ((int8_t)(ds18b20_device_scratchpad[1] << 4) + (ds18b20_device_scratchpad[0] >> 4) + ((double)(ds18b20_device_scratchpad[0] & 0x0F) / 16));
ds18b20_device_scratchpad_temp_dec = ((double)(ds18b20_device_scratchpad[0] & 0x0F) / 16 * 1000);
ds18b20_raw_temp = ((ds18b20_device_scratchpad[1] << 8) | ds18b20_device_scratchpad[0]);
ds18b20_device_scratchpad_temp = (double)ds18b20_raw_temp / 16;
ds18b20_device_scratchpad_temp_dec = (ds18b20_raw_temp - (ds18b20_raw_temp / 16 * 16)) * 1000 / 16;
if (ds18b20_device_scratchpad_conf >= ds18b20_device_res) {
ds18b20_device_res = ds18b20_device_scratchpad_conf;