Merge pull request #3412 from leptun/MK3_TWI_timeout

Hardware TWI timeout

Firmware/pat9125.h

@@ -4,12 +4,6 @@
 
 #include <inttypes.h>
 
-
-#if defined(__cplusplus)
-extern "C" {
-#endif //defined(__cplusplus)
-
-
 extern uint8_t pat9125_PID1;
 extern uint8_t pat9125_PID2;
 
@@ -24,9 +18,4 @@ extern uint8_t pat9125_update(void);    // update all sensor data
 extern uint8_t pat9125_update_y(void);  // update _y only
 extern uint8_t pat9125_update_bs(void); // update _b/_s only
 
-
-#if defined(__cplusplus)
-}
-#endif //defined(__cplusplus)
-
 #endif //PAT9125_H

Firmware/twi.cpp

@@ -24,6 +24,7 @@
 #include "config.h"
 #include "fastio.h"
 #include "twi.h"
+#include "Timer.h"
 
 
 void twi_init(void)
@@ -44,6 +45,9 @@ void twi_init(void)
 
 void twi_disable(void)
 {
+  // disable TWI hardware.
+  TWCR = 0;
+  
   // deactivate internal pullups for twi.
   WRITE(SDA_PIN, 0);
   WRITE(SCL_PIN, 0);
@@ -58,7 +62,13 @@ static void twi_stop()
 
 static uint8_t twi_wait(uint8_t status)
 {
-  while(!(TWCR & _BV(TWINT)));
+  ShortTimer timmy;
+  timmy.start();
+  while(!(TWCR & _BV(TWINT))) {
+    if (timmy.expired(TWI_TIMEOUT_MS)) {
+      return 2;
+    }
+  }
   if(TW_STATUS != status)
   {
       twi_stop();

Firmware/twi.h

@@ -26,6 +26,8 @@
 #define TWI_FREQ 400000L
 #endif
 
+#define TWI_TIMEOUT_MS 100
+
 /*
  * Function twi_init
  * Desc     readys twi pins and sets twi bitrate