From 6b6d46c3e1fa2c05aee87d84c197ea620efb7370 Mon Sep 17 00:00:00 2001
From: "David A. Mellis" <d.mellis@arduino.cc>
Date: Wed, 11 Aug 2010 22:59:00 +0000
Subject: Adding shiftIn() from Wiring (no count or delaytime though).

---
 cores/arduino/wiring_shift.c | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

(limited to 'cores/arduino/wiring_shift.c')

diff --git a/cores/arduino/wiring_shift.c b/cores/arduino/wiring_shift.c
index 956f864..cfe7867 100755
--- a/cores/arduino/wiring_shift.c
+++ b/cores/arduino/wiring_shift.c
@@ -24,9 +24,24 @@
 
 #include "wiring_private.h"
 
-void shiftOut(uint8_t dataPin, uint8_t clockPin, uint8_t bitOrder, byte val)
+uint8_t shiftIn(uint8_t dataPin, uint8_t clockPin, uint8_t bitOrder) {
+	uint8_t value = 0;
+	uint8_t i;
+
+	for (i = 0; i < 8; ++i) {
+		digitalWrite(clockPin, HIGH);
+		if (bitOrder == LSBFIRST)
+			value |= digitalRead(dataPin) << i;
+		else
+			value |= digitalRead(dataPin) << (7 - i);
+		digitalWrite(clockPin, LOW);
+	}
+	return value;
+}
+
+void shiftOut(uint8_t dataPin, uint8_t clockPin, uint8_t bitOrder, uint8_t val)
 {
-	int i;
+	uint8_t i;
 
 	for (i = 0; i < 8; i++)  {
 		if (bitOrder == LSBFIRST)
-- 
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