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--- 2011:arduino_to_avr_pin_mapping [2011/08/07 10:15] – tomgee
+++ 2011:arduino_to_avr_pin_mapping [2011/10/14 09:34] (current) – tomgee
@@ Line 4: / Line 4: @@
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+Using Port C as digital output (Read 1072 times)
+Using Port C as digital output
+.02.2010 at 16:14:06
+It took me a bit of time to extract this info from the docs and the board itself, so I thought I'd post it here so any searchers in the future will get there quicker.
+This is for the Duemilanove
+   //Using Port C as digital output
+In your setup:
+   // Turn analog inputs to digital outputs
+   DDRC=0xFF ; // These will be pin numbers 14 .. 19
+In your loop:
+   digitalWrite (14, HIGH);
+   // ...etc...
+   digitalWrite (19, LOW);
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+Re: Using Port C as digital output
+Reply #1 - 03.02.2010 at 16:20:51
+I don't think there's any need for anything in setup, it's all already done by digitalRead/digitalWrite when you specify the correct pin numbers.
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+Re: Using Port C as digital output
+Reply #2 - 03.02.2010 at 18:54:04
+That's true as long as you initialize the pins to OUTPUT before you use digitalWrite().
+ pinMode(14, OUTPUT);
+ pinMode(19, OUTPUT);
+That's traditionally done in setup().
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+Re: Using Port C as digital output
+Reply #3 - 03.02.2010 at 20:09:14
+Quote:
+// Turn analog inputs to digital outputs
+  DDRC=0xFF ; // These will be pin numbers 14 .. 19
+The DDRC register determines data direction (input or output) for port-C.
+Setting all bits to one (as in your code) will configure the pins for output. It
+is not related to switching between analog/digital (no command is needed for
+this).
+Port C includes the RESET pin on PC6 and an undefined pin on PC7. PC0 thru PC5
+map to Arduino A0 (14) thru to A5 (19). Forcing RESET to become an output pin
+(as would be the case with your statement)  is not something you want to do
+unless the ATmega chip is refused to disable/ignore RESET. Also it is not good
+practice to force an undefined pin (A7) to any value - rather you should leave
+it as is (DDRC|=0x3f would be ok).
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+Re: Using Port C as digital output
+Reply #4 - 04.02.2010 at 07:07:14
+So, I should actually do:
+ // Turn analog inputs to digital outputs
+ DDRC=0x3F ; // These will be pin numbers 14 .. 19
+is that right?
+I posted this because I could not find any clear examples of using these pins.
+And you say:
+"PC0 thru PC5 map to Arduino A0 (14) thru to A5 (19)."
+which I understand, but what is the advised way of naming these pins. 14 ... 19. I can't find the C define for "A0" or PC0.
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+Re: Using Port C as digital output
+Reply #5 - 04.02.2010 at 08:17:14
+The Arduino way would be as follows:
+Code:
+  pinMode(14,OUTPUT); // configure A0 for output
+  digitalWrite(14,HIGH); // set PORTC pin 0 high
+Direct PORT IO is as follows:
+Code:
+  DDRC |= _BV(PORTC0); // configure A0 for output
+  PORTC |= _BV(PORTC0); // set PORTC pin 0 high
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