From 2a465d26c1c5209446f0d5c46a964019fcf5bce1 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Fri, 1 Nov 2013 00:14:23 +0200
Subject: [PATCH] Fix S88 latching logic

---
 s88w/s88w-r.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/s88w/s88w-r.c b/s88w/s88w-r.c
index 1716532..f94a1be 100644
--- a/s88w/s88w-r.c
+++ b/s88w/s88w-r.c
@@ -42,9 +42,11 @@ uint8_t rx_buf[7];
 uint8_t rx_fill = 0xFF;
 uint8_t input[128] = { 0 };
 uint8_t latch[128] = { 0 };
+uint8_t output[128] = { 0 };
 uint8_t out_offset = 0;
 uint8_t out_bits = 0;
 uint8_t out_fill = 0;
+volatile uint8_t load_pos = 0xFF;
 volatile uint8_t reset_pos = 0xFF;
 uint8_t lcd_enabled = 0;
 uint8_t log_row = 0;
@@ -70,6 +72,15 @@ int main()
 
 		check_input();
 
+		i = load_pos;
+		if(i!=0xFF)
+		{
+			output[i] = latch[i];
+			if(++i>=sizeof(input))
+				i = 0xFF;
+			load_pos = i;
+		}
+
 		i = reset_pos;
 		if(i!=0xFF)
 		{
@@ -134,7 +145,7 @@ void check_input()
 					uint8_t shift = 4*(j&1);
 					uint8_t bits = decode_hex(rx_buf[3+i]);
 					input[j/2] = (input[j/2]&~(0xF<<shift)) | (bits<<shift);
-					latch[j/2] = input[j/2];
+					latch[j/2] |= input[j/2];
 				}
 
 				if(lcd_enabled)
@@ -203,6 +214,7 @@ ISR(PCINT2_vect)
 				out_offset = 0;
 				out_bits = latch[0];
 				out_fill = 8;
+				load_pos = 0;
 			}
 
 			if(out_bits&1)
@@ -214,7 +226,7 @@ ISR(PCINT2_vect)
 			if(!--out_fill)
 			{
 				++out_offset;
-				out_bits = latch[out_offset];
+				out_bits = output[out_offset];
 				out_fill = 8;
 			}
 
-- 
2.43.0