fix negative numbers bug in dewpoint

F1-nolib/BMP280/BMP280.c

@@ -135,7 +135,7 @@ static struct{
     uint8_t ID;                 // identificator
     uint8_t regctl;             // control register base value [(params.t_os << 5) | (params.p_os << 2)]
 } params = {
-    .filter = BMP280_FILTER_16,
+    .filter = BMP280_FILTER_OFF,
     .p_os   = BMP280_OVERS16,
     .t_os   = BMP280_OVERS16,
     .h_os   = BMP280_OVERS16,

F1-nolib/BMP280/BMP280.h

@@ -52,12 +52,12 @@
 #define BMP280_CHIP_ID  0x58
 #define BME280_CHIP_ID  0x60
 
-typedef enum{ // Nsamples for filtering
-    BMP280_FILTER_OFF = 0,
-    BMP280_FILTER_2   = 1,
-    BMP280_FILTER_4   = 2,
-    BMP280_FILTER_8   = 3,
-    BMP280_FILTER_16  = 4,
+typedef enum{ // K for filtering: next = [prev*(k-1) + data_ADC]/k
+    BMP280_FILTER_OFF = 0, // k=1, no filtering
+    BMP280_FILTER_2   = 1, // k=2, 2 samples to reach >75% of data_ADC
+    BMP280_FILTER_4   = 2, // k=4, 5 samples
+    BMP280_FILTER_8   = 3, // k=8, 11 samples
+    BMP280_FILTER_16  = 4, // k=16, 22 samples
     BMP280_FILTERMAX
 } BMP280_Filter;
 

F1-nolib/BMP280/main.c

@@ -55,7 +55,7 @@ static char *get_USB(){
 
 static void showd(int32_t mT, int32_t mH){
     USB_send("Dewpoint=");
-    USB_send(u2str(dewpoint(mT, mH)));
+    USB_send(i2str(dewpoint(mT, mH)));
     USB_send("*10degrC\n");
 }
 

F1-nolib/BMP280/proto.c

@@ -280,4 +280,3 @@ char *i2str(int32_t i){
     }else val = i;
     return _2str(val, minus);
 }
-

F1-nolib/SI7005_HTU21D/main.c

@@ -57,7 +57,12 @@ char *get_USB(){
 void showd(int32_t mT, int32_t mH){
     if(mT == -10000 || mH == -10000) return;
     USB_send("Dewpoint=");
-    USB_send(u2str(dewpoint(mT, mH)));
+    int32_t d = dewpoint(mT, mH);
+    if(d < 0){
+        USB_send("-");
+        d = -d;
+    }
+    USB_send(u2str(d));
     USB_send("*10degrC\n");
 }