1 files changed, 34 insertions, 4 deletions
diff --git a/emu/7seg.h b/emu/7seg.h
index c49a8a1..0cd585f 100644
--- a/emu/7seg.h
+++ b/emu/7seg.h
@@ -1,12 +1,42 @@
-#ifndef 7_SEG_H
-#define 7_SEG_H
+#ifndef SEG7_H
+#define SEG7_H
 
 #ifdef WITH_GUI
 #include <SDL.h>
 #endif
 
-typedef struct 7seg_t
+#include <stdint.h>
+#include <stdbool.h>
+
+// VIA connected on PORTA to 3 wires leading to the 3 coupled 74HC595
+// shift register which enable the ROM address lines to read the LED
+// segment data (cells 0-15 contain the encoded 7 segments of 16 hexdigits)
+//
+// PORTA connected as follows:
+// xxxxx111
+//        +--- SER
+//       +---- RCLK
+//      +----- SRCLK
+enum {
+	PORTA = 0x6001,
+	DDRA  = 0x6003,
+	
+	SER   = 0x01,
+	RCLK  = 0x02,
+	SRCLK = 0x04
+};
+
+typedef struct seg7_t
 {
-} 7seg_t;
+	uint8_t ddr;
+	uint16_t shift;
+	uint16_t latch;
+
+	bool debug;
+} seg7_t;
+
+void seg7_init( seg7_t *seg );
+uint8_t seg7_read( seg7_t *seg, uint16_t addr );
+void seg7_write( seg7_t *seg, uint16_t addr, uint8_t data );
 
 #endif