From 827bcdb38627e5ff7d1809fb9ea9ef4bb5ccf386 Mon Sep 17 00:00:00 2001
From: Dreaded_X <tim.huizinga@gmail.com>
Date: Wed, 30 Dec 2020 21:04:37 +0100
Subject: [PATCH] Added buffering to output

---
 include/keyboard.h |  4 ++++
 src/main.c         | 39 +++++++++++++++++++++++++++++++++------
 2 files changed, 37 insertions(+), 6 deletions(-)

diff --git a/include/keyboard.h b/include/keyboard.h
index b63841c..2322987 100644
--- a/include/keyboard.h
+++ b/include/keyboard.h
@@ -3,6 +3,10 @@
 
 #include <stdint.h>
 
+// SCHEMATIC
+// #define KEYBOARD_CLK 2
+// #define KEYBOARD_DATA 3
+
 #define KEYBOARD_CLK 2
 #define KEYBOARD_DATA 7
 
diff --git a/src/main.c b/src/main.c
index c76ff59..0466743 100644
--- a/src/main.c
+++ b/src/main.c
@@ -5,9 +5,18 @@
 
 #include "scancode.h"
 #include "keyboard.h"
+#include "fifo.h"
 
+// SCHEMATIC
+/* #define CLK 4 */
+/* #define DATA 5 */
+/* #define RDY 6 */
+/* #define WAIT 7 */
+
+#define RDY 3
 #define CLK 4
 #define DATA 5
+#define WAIT 6
 
 // Clock the value to 74164
 void write_value(uint8_t value) {
@@ -16,24 +25,34 @@ void write_value(uint8_t value) {
 		PORTD |= (1<<CLK) | (bit<<DATA);
 		PORTD &= ~((1<<CLK) | (bit<<DATA));
 	}
+
+	// Indicate that a byte is waiting
+	PORTD &= ~(1<<RDY);
+	PORTD |= (1<<RDY);
+}
+
+volatile struct FIFO buffer;
+
+void add_to_queue(uint8_t c) {
+	FIFO_push(&buffer, c);
 }
 
 ISR(PCINT2_vect) {
-	keyboard_interrupt(write_value);
+	keyboard_interrupt(add_to_queue);
 }
 
 int main() {
 	// Configure pins as output
-	DDRD |= (1<<CLK) | (1<<DATA);
+	DDRD |= (1<<RDY) | (1<<CLK) | (1<<DATA);
+	PORTD |= (1<<RDY);
 
-	DDRD &= ~((1<<KEYBOARD_CLK) | (1<<KEYBOARD_DATA));
+	// Configure pins as input
+	DDRD &= ~((1<<KEYBOARD_CLK) | (1<<KEYBOARD_DATA) | (1<<WAIT));
 
 	// interrupt
 	PCMSK2 |= (1<<PCINT18);
 	PCICR |= (1<<PCIE2);
 
-	write_value(0);
-
 	sei();
 
 	// Wait for the keyboard to be ready
@@ -45,9 +64,17 @@ int main() {
 
 	// Set the keyboard repeat rate (and delay)
 	send_keyboard_cmd(0xF3);
-	send_keyboard_cmd(0x00 | (1<<5) | (1<<4));
+	send_keyboard_cmd(0x00 | (0<<5) | (0<<4));
 
 	for (;;) {
 		send_keyboard_cmd_queue();
+
+		if (FIFO_size(&buffer) && !(PIND>>WAIT & 1)) {
+			// We currently need this to make sure that RDY gets set
+			// However that is possibly because of the button
+			// And might not be a problem on actual hardware
+			_delay_ms(1);
+			write_value(FIFO_pop(&buffer));
+		}
 	}
 }