From 4c6cb2e5c4748502cbd26d3bd38e490ebead197f Mon Sep 17 00:00:00 2001
From: Daniel Friesel <derf@finalrewind.org>
Date: Fri, 15 Jan 2016 20:27:22 +0100
Subject: turn modem voltage divider off during sleep

needs hw revision >= git commit 71f427bd100963b1aafb545bfca319c50e1c48cd
---
 src/main.cc   | 12 +++++++++---
 src/modem.cc  | 14 ++++++++++++--
 src/modem.h   |  3 ++-
 src/system.cc |  9 +++++++--
 4 files changed, 30 insertions(+), 8 deletions(-)

diff --git a/src/main.cc b/src/main.cc
index eb523ce..03cdabd 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -33,8 +33,14 @@ int main (void)
 	// raise timer interrupt on counter overflow (-> interrupt frequency = ~4kHz)
 	TIMSK0 = _BV(TOIE0);
 
-	disp[0] = 0xff;
-	disp[1] = 0xaa;
+	disp[0] = 0x01;
+	disp[1] = 0x02;
+	disp[2] = 0x04;
+	disp[3] = 0x08;
+	disp[4] = 0x10;
+	disp[5] = 0x20;
+	disp[6] = 0x40;
+	disp[7] = 0x80;
 
 #if 0
 	// smile!
@@ -72,7 +78,7 @@ int main (void)
 	disp[31] = 0x00;
 #endif
 
-	modem.init();
+	modem.enable();
 
 	sei();
 
diff --git a/src/modem.cc b/src/modem.cc
index cb3a6ee..2eae685 100644
--- a/src/modem.cc
+++ b/src/modem.cc
@@ -28,7 +28,7 @@ uint8_t Modem::buffer_available() {
  * Store 1 byte in ringbuffer
  */
 static inline void modem_buffer_put(const uint8_t c) {
-	if (modem.buffer_available() != MODEM_BUFFER_SIZE) { 
+	if (modem.buffer_available() != MODEM_BUFFER_SIZE) {
 		modem_buffer[modem_buffer_head++ % MODEM_BUFFER_SIZE] = c;
 	} 
 }
@@ -83,7 +83,11 @@ ISR(PCINT3_vect) {
 /*
  * Start the modem by enabling Pin Change Interrupts & Timer
  */
-void Modem::init()  {
+void Modem::enable()  {
+	/* Enable R1 */
+	DDRA  |= _BV(PA3);
+	PORTA |= _BV(PA3);
+
 	/* Modem pin as input */
 	MODEM_DDR &= ~_BV(MODEM_PIN);
 
@@ -94,3 +98,9 @@ void Modem::init()  {
 	/* Timer: TCCR1: CS10 and CS11 bits: 8MHz clock with Prescaler 64 = 125kHz timer clock */
 	TCCR1B = _BV(CS11) | _BV(CS10);
 }
+
+void Modem::disable()
+{
+	PORTA &= ~_BV(PA3);
+	DDRA  &= ~_BV(PA3);
+}
diff --git a/src/modem.h b/src/modem.h
index 9c629a5..a37d7d8 100644
--- a/src/modem.h
+++ b/src/modem.h
@@ -27,7 +27,8 @@ class Modem {
 		Modem() {};
 		uint8_t buffer_available(void);
 		uint8_t buffer_get(void);
-		void init(void);
+		void enable(void);
+		void disable(void);
 };
 
 extern Modem modem;
diff --git a/src/system.cc b/src/system.cc
index 9aaa62b..b98e687 100644
--- a/src/system.cc
+++ b/src/system.cc
@@ -34,6 +34,8 @@ void System::loop()
 			// turn off display to indicate we're about to shut down
 			display.turn_off();
 
+			modem.disable();
+
 			// wait until both buttons are released
 			while (!((PINC & _BV(PC3)) && (PINC & _BV(PC7)))) ;
 
@@ -57,6 +59,9 @@ void System::loop()
 			// turn on display
 			display.turn_on();
 
+			// ... and modem
+			modem.enable();
+
 			want_shutdown = 0;
 		}
 	}
@@ -64,9 +69,9 @@ void System::loop()
 		want_shutdown = 0;
 	}
 
-	if (modem.buffer_available()) {
+	while (modem.buffer_available()) {
 		disp[i++] = modem.buffer_get();
-		if (i == 7)
+		if (i == 8)
 			i = 0;
 	}
 }
-- 
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