From 79236eaaced258e4e34619ea9210faf7e621fd8e Mon Sep 17 00:00:00 2001
From: Trygve Laugstøl <trygvis@inamo.no>
Date: Mon, 2 Apr 2012 15:32:26 +0200
Subject: o Start of temperature reader.

---
 firmware/VirtualSerial.c | 93 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 93 insertions(+)

diff --git a/firmware/VirtualSerial.c b/firmware/VirtualSerial.c
index 0fdc31c..cc06237 100644
--- a/firmware/VirtualSerial.c
+++ b/firmware/VirtualSerial.c
@@ -40,6 +40,8 @@
 
 static int running = true;
 
+void CheckACMStatus(void);
+
 /** LUFA CDC Class driver interface configuration and state information. This structure is
  *  passed to all CDC Class driver functions, so that multiple instances of the same class
  *  within a device can be differentiated from one another.
@@ -90,6 +92,85 @@ void lock_timer_reset(void)
         lock_timer_ticks = 0;
 }
 
+#define LM74_SIO PD4
+#define LM74_SCL PD5
+#define LM74_CS  PD3
+
+/**
+ * Data is clocked out on the falling edge of the serial clock (SC), while data is clocked in on the rising edge of SC.
+ */
+void lm74_transaction(uint8_t out1, uint8_t out2, uint8_t *in1, uint8_t *in2)
+{
+/*
+        for(int i = 0; i < 8; i++)
+        {
+                PORTD |= (out1 & 0x01) << LM74_SIO;
+                PORTD |= _BV(LM74_SCL);
+                PORTD &= ~_BV(LM74_SCL);
+                out1 >>= 1;
+        }
+
+        for(int i = 0; i < 8; i++)
+        {
+                PORTD |= (out2 & 0x01) << LM74_SIO;
+                PORTD |= _BV(LM74_SCL);
+                PORTD &= ~_BV(LM74_SCL);
+                out2 >>= 1;
+        }
+*/
+/*
+        for(int i = 0; i < 16; i++)
+        {
+//                PORTD |= (out2 & 0x01) << LM74_SIO;
+                PORTD |= _BV(LM74_SCL);
+                _delay_ms(10);
+                PORTD &= ~_BV(LM74_SCL);
+                _delay_ms(10);
+        }
+*/
+        uint16_t temp;
+
+        PORTD &= ~_BV(LM74_CS);
+        _delay_us(100);
+        for(int i=0; i<16; i++) {
+                temp <<= 1;
+                PORTD |= _BV(LM74_SCL);
+                _delay_us(100);
+//                if (SIO == true)
+//                        temp |= 1;
+                PORTD &= ~_BV(LM74_SCL);
+                _delay_us(100);
+        }
+
+        PORTD |= _BV(LM74_CS);
+}
+
+void lm74_init(void)
+{
+        PORTD |= (1 << LM74_SCL) | (1 << LM74_CS);
+
+        DDRD |= (1 << LM74_SCL) | (1 << LM74_CS);
+        DDRD &= ~(1 << LM74_SIO);
+
+        PORTD |= (1 << LM74_SIO); // Enable pull-up
+
+        uint8_t d1, d2;
+        _delay_ms(100);
+        lm74_transaction(0x5a, 0xa5, &d1, &d2);
+        _delay_ms(100);
+        lm74_transaction(0x5a, 0xa5, &d1, &d2);
+        _delay_ms(100);
+        lm74_transaction(0x5a, 0xa5, &d1, &d2);
+        _delay_ms(100);
+        lm74_transaction(0x5a, 0xa5, &d1, &d2);
+        _delay_ms(100);
+        lm74_transaction(0x5a, 0xa5, &d1, &d2);
+        _delay_ms(100);
+        lm74_transaction(0x5a, 0xa5, &d1, &d2);
+        _delay_ms(100);
+        lm74_transaction(0x5a, 0xa5, &d1, &d2);
+}
+
 /** Main program entry point. This routine contains the overall program flow, including initial
  *  setup of all components and the main program loop.
  */
@@ -98,7 +179,11 @@ int main(void)
 	DDRB = 1 << PB0 | 1 << PB4 | 0 << PB5;
 	PORTB = 0 << PB0;
 
+    // Disables pull-ups
+	PORTD = 0;
+
 	SetupHardware();
+    lm74_init();
 
 	lock_timer_setup();
 
@@ -183,6 +268,14 @@ void handle_command(const char *buf)
 	PORTB &= ~(1 << PB4);
 	PORTB &= ~(1 << PB0);
     }
+
+    else if (strcmp("temp", buf) == 0)
+    {
+	uint8_t data = 0x5a;
+
+        uint8_t d1, d2;
+        lm74_transaction(0x5a, 0xa5, &d1, &d2);
+    }
 }
 
 void CheckACMStatus()
-- 
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