From abf69bd53f86300d263d3abeeae81a9e1c3cd5c0 Mon Sep 17 00:00:00 2001
From: Daniel Friesel <derf@finalrewind.org>
Date: Tue, 19 Jan 2016 19:59:51 +0100
Subject: support scrolling arbitrary strings.

---
 src/display.cc | 48 ++++++++++++++++++++++++++++++++++--------------
 src/display.h  |  1 +
 src/font.h     |  1 +
 src/main.cc    | 52 ++++++----------------------------------------------
 src/system.cc  | 11 +++++++----
 5 files changed, 49 insertions(+), 64 deletions(-)

diff --git a/src/display.cc b/src/display.cc
index b1b0af5..4215983 100644
--- a/src/display.cc
+++ b/src/display.cc
@@ -5,10 +5,11 @@
 #include <stdlib.h>
 
 #include "display.h"
+#include "font.h"
 
 Display display;
 
-extern volatile uint8_t disp[8];
+uint8_t teststr[] = {'O', 'h', 'a', 'i', '!', 0};
 
 void Display::disable()
 {
@@ -41,22 +42,14 @@ ISR(TIMER0_OVF_vect)
 {
 	static uint8_t active_col = 0;
 	static uint16_t scroll = 0;
-	static uint8_t disp_offset = 0;
 
-	static uint8_t disp_buf[8];
+	static uint8_t disp_buf[] = {0xff,0xfb,0xdd,0xfd,0xdd,0xfb,0xff,0xff};
 
-	uint8_t i;
+	static uint8_t str_pos = 0;
+	static int8_t char_pos = -1;
 
-	if (++scroll == 512) {
-		scroll = 0;
-		if (++disp_offset == sizeof(disp)) {
-			disp_offset = 0;
-		}
-
-		for (i = 0; i < 8; i++) {
-			disp_buf[i] = ~disp[(disp_offset + i) % sizeof(disp)];
-		}
-	}
+	uint8_t i, glyph_len;
+	uint8_t *glyph_addr;
 
 	/*
 	 * To avoid flickering, do not put any code (or expensive index
@@ -68,4 +61,31 @@ ISR(TIMER0_OVF_vect)
 
 	if (++active_col == 8)
 		active_col = 0;
+
+	if (++scroll == 512) {
+		scroll = 0;
+
+		for (i = 0; i < 7; i++) {
+			disp_buf[i] = disp_buf[i+1];
+		}
+
+		glyph_addr = (uint8_t *)pgm_read_ptr(&font[(uint8_t)display.string[str_pos]]);
+		glyph_len = pgm_read_byte(&glyph_addr[0]);
+		char_pos++;
+
+		if (char_pos > glyph_len) {
+			char_pos = 0;
+			str_pos++;
+		}
+
+		if (display.string[str_pos] == 0) {
+			str_pos = 0;
+		}
+
+		if (char_pos == 0) {
+			disp_buf[7] = 0xff; // whitespace
+		} else {
+			disp_buf[7] = ~pgm_read_byte(&glyph_addr[char_pos]);
+		}
+	}
 }
diff --git a/src/display.h b/src/display.h
index cb263d0..d239e18 100644
--- a/src/display.h
+++ b/src/display.h
@@ -9,6 +9,7 @@ class Display {
 		Display() {};
 		void enable(void);
 		void disable(void);
+		char string[128];
 };
 
 extern Display display;
diff --git a/src/font.h b/src/font.h
index aea6b8a..a705d57 100644
--- a/src/font.h
+++ b/src/font.h
@@ -133,6 +133,7 @@ const unsigned char PROGMEM chr_125[] = {0x03,0x41,0x36,0x08}; // }
 const unsigned char PROGMEM chr_126[] = {0x05,0x08,0x10,0x08,0x04,0x08}; // ~
 
 const glyph_t font[] PROGMEM = {
+	chr_001,
 	chr_001,
 	chr_002,
 	chr_003,
diff --git a/src/main.cc b/src/main.cc
index fbb40c9..f665e18 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -9,8 +9,6 @@
 #include "modem.h"
 #include "system.h"
 
-volatile uint8_t disp[8];
-
 int main (void)
 {
 	// disable ADC to save power
@@ -22,50 +20,12 @@ int main (void)
 	// Enable pull-ups on PC3 and PC7 (button pins)
 	PORTC |= _BV(PC3) | _BV(PC7);
 
-	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!
-	disp[0] = 0x08;
-	disp[1] = 0x04;
-	disp[2] = 0x62;
-	disp[3] = 0x02;
-	disp[4] = 0x02;
-	disp[5] = 0x62;
-	disp[6] = 0x04;
-	disp[7] = 0x08;
-	disp[8] = 0x00;
-	disp[9] = 0x00;
-	disp[10] = 0x00;
-	disp[11] = 0x00;
-	disp[12] = 0x00;
-	disp[13] = 0x00;
-	disp[14] = 0x00;
-	disp[15] = 0x00;
-	disp[16] = 0x28;
-	disp[17] = 0x44;
-	disp[18] = 0x22;
-	disp[19] = 0x02;
-	disp[20] = 0x02;
-	disp[21] = 0x22;
-	disp[22] = 0x44;
-	disp[23] = 0x28;
-	disp[24] = 0x00;
-	disp[25] = 0x00;
-	disp[26] = 0x00;
-	disp[27] = 0x00;
-	disp[28] = 0x00;
-	disp[29] = 0x00;
-	disp[30] = 0x00;
-	disp[31] = 0x00;
-#endif
+	display.string[0] = 'O';
+	display.string[1] = 'h';
+	display.string[2] = 'a';
+	display.string[3] = 'i';
+	display.string[4] = '!';
+	display.string[5] = 0;
 
 	display.enable();
 	modem.enable();
diff --git a/src/system.cc b/src/system.cc
index 09c0f53..340615d 100644
--- a/src/system.cc
+++ b/src/system.cc
@@ -12,11 +12,10 @@
 
 System rocket;
 
-extern volatile uint8_t disp[8];
-
 void System::loop()
 {
 	static uint8_t i = 0;
+	char modem_char;
 	// both buttons are pressed
 	if ((PINC & (_BV(PC3) | _BV(PC7))) == 0) {
 		// naptime!
@@ -70,9 +69,13 @@ void System::loop()
 	}
 
 	while (modem.buffer_available()) {
-		disp[i++] = modem.buffer_get();
-		if (i == 8)
+		modem_char = modem.buffer_get();
+		display.string[i++] = modem_char;
+		if (i == 127) {
+			i = 0;
+		} else if (modem_char == 0) {
 			i = 0;
+		}
 	}
 }
 
-- 
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