Adding INPUT_PULLUP option pinMode(). (Paul Stoffregen).
This also changes pinMode(pin, INPUT); to explicitly disable the pull-up resistor, even if it was previously set. http://code.google.com/p/arduino/issues/detail?id=246
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@ -20,6 +20,7 @@ extern "C"{
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#define INPUT 0x0
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#define OUTPUT 0x1
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#define INPUT_PULLUP 0x2
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#define true 0x1
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#define false 0x0
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@ -32,17 +32,25 @@ void pinMode(uint8_t pin, uint8_t mode)
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{
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uint8_t bit = digitalPinToBitMask(pin);
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uint8_t port = digitalPinToPort(pin);
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volatile uint8_t *reg;
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volatile uint8_t *reg, *out;
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if (port == NOT_A_PIN) return;
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// JWS: can I let the optimizer do this?
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reg = portModeRegister(port);
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out = portOutputRegister(port);
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if (mode == INPUT) {
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uint8_t oldSREG = SREG;
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cli();
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*reg &= ~bit;
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*out &= ~bit;
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SREG = oldSREG;
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} else if (mode == INPUT_PULLUP) {
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uint8_t oldSREG = SREG;
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cli();
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*reg &= ~bit;
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*out |= bit;
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SREG = oldSREG;
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} else {
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uint8_t oldSREG = SREG;
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