Only update pull-up value in digitalWrite if pin direction is not output

sandeepmistry · sandeepmistry · commit 0f3f80a1ccfb · 2016-01-21T14:20:00.000-05:00
diff --git a/cores/arduino/wiring_digital.c b/cores/arduino/wiring_digital.c
@@ -82,8 +82,10 @@ void digitalWrite( uint32_t ulPin, uint32_t ulVal )
     return ;
   }
 
-  // Enable pull-up resistor
-  PORT->Group[g_APinDescription[ulPin].ulPort].PINCFG[g_APinDescription[ulPin].ulPin].reg=(uint8_t)(PORT_PINCFG_PULLEN) ;
+  if ( (PORT->Group[g_APinDescription[ulPin].ulPort].DIRSET.reg & (1ul << g_APinDescription[ulPin].ulPin)) == 0 ) {
+    // the pin is not an output, disable pull-up if val is LOW, otherwise enable pull-up
+    PORT->Group[g_APinDescription[ulPin].ulPort].PINCFG[g_APinDescription[ulPin].ulPin].bit.PULLEN = (ulVal != LOW) ;
+  }
 
   switch ( ulVal )
   {

Original file line number	Diff line number	Diff line change
`@@ -82,8 +82,10 @@ void digitalWrite( uint32_t ulPin, uint32_t ulVal )`
`82`	`82`	`return ;`
`83`	`83`	`}`
`84`	`84`
`85`		`- // Enable pull-up resistor`
`86`		`- PORT->Group[g_APinDescription[ulPin].ulPort].PINCFG[g_APinDescription[ulPin].ulPin].reg=(uint8_t)(PORT_PINCFG_PULLEN) ;`
	`85`	`+ if ( (PORT->Group[g_APinDescription[ulPin].ulPort].DIRSET.reg & (1ul << g_APinDescription[ulPin].ulPin)) == 0 ) {`
	`86`	`+ // the pin is not an output, disable pull-up if val is LOW, otherwise enable pull-up`
	`87`	`+ PORT->Group[g_APinDescription[ulPin].ulPort].PINCFG[g_APinDescription[ulPin].ulPin].bit.PULLEN = (ulVal != LOW) ;`
	`88`	`+ }`
`87`	`89`
`88`	`90`	`switch ( ulVal )`
`89`	`91`	`{`