SPI2 cleanups

src/ads7846.c

@@ -19,8 +19,6 @@ static inline double ads7846RangeMap(double oldMin, double oldMax, double value,
 }
 
 static inline bool ads7846GetAdcBit(){
-   //a new control byte can be sent while receiving data
-   //this is valid behavior as long as the start of the last control byte was 16 or more clock cycles ago
    bool bit = ads7846OutputValue & 0x8000;
    ads7846OutputValue <<= 1;
    return bit;
@@ -85,11 +83,17 @@ void ads7846SetChipSelect(bool value){
 }
 
 bool ads7846ExchangeBit(bool bitIn){
+   //chip data out is high when off
+   if(ads7846ChipSelect)
+      return true;
+
    if(ads7846BitsToNextControl > 0)
       ads7846BitsToNextControl--;
 
    if(ads7846BitsToNextControl == 0){
       //check for control bit
+      //a new control byte can be sent while receiving data
+      //this is valid behavior as long as the start of the last control byte was 16 or more clock cycles ago
       if(bitIn){
          ads7846ControlByte = 0x01;
          ads7846BitsToNextControl = 15;

src/hardwareRegistersAccessors.c.h

@@ -305,19 +305,20 @@ static inline void setSpiCont2(uint16_t value){
       uint16_t startBit = 1 << (bitCount - 1);
       uint16_t spi2Data = registerArrayRead16(SPIDATA2);
       bool spiClk2Enabled = !(registerArrayRead8(PESEL) & 0x04);
-      bool ads7846ChipSelect = !(getPortGValue() & 0x04);//this is unproven, but having it high makes the ADS7846 not work on hardware
       //uint16_t oldSpi2Data = spi2Data;
 
       //the input data is shifted into the unused bits if the transfer is less than 16 bits
-      for(uint8_t bits = 0; bits < bitCount; bits++){
-         bool newBit = true;
-
-         if(spiClk2Enabled && ads7846ChipSelect)
-            newBit = ads7846ExchangeBit(spi2Data & startBit);
-
-         //debugLog("Sent Bit:%d\n", (bool)(spi2Data & startBit));
-         spi2Data <<= 1;
-         spi2Data |= newBit;
+      if(spiClk2Enabled){
+         //shift in valid data
+         for(uint8_t bits = 0; bits < bitCount; bits++){
+            bool newBit = ads7846ExchangeBit(spi2Data & startBit);
+            spi2Data <<= 1;
+            spi2Data |= newBit;
+         }
+      }
+      else{
+         //shift in 0s
+         spi2Data <<= bitCount;
       }
       registerArrayWrite16(SPIDATA2, spi2Data);
 

unimplementedHardware.txt

@@ -42,6 +42,7 @@ ADS7846:
 verify chip select(no test has been done yet, put everything points to port g bit 2)
 need to trigger a false PENIRQ interrupt on reading certain channels
 electrical noise on lines(conversions probably should have +-20 added to values)(probably no need for this, it works so theres no need to use less precise values)
+in the edge case that SPICLK2 is disabled while using ADS7846 and a 1 was the last bit shifted out 0s will still be shifted in
 
 
 Fixed: