Refactor timers, add GPIO debugging, and increase print speed

Makefile

@@ -8,7 +8,11 @@ clean:
 	rm -rf build
 
 sim: build/ec.rom
-	cargo run --release --manifest-path ecsim/Cargo.toml -- $<
+	cargo run \
+		--release \
+		--manifest-path ecsim/Cargo.toml \
+		--no-default-features \
+		-- $<
 
 build/ec.rom: build/ec.ihx
 	mkdir -p build

src/delay.c

@@ -1,30 +1,18 @@
 #include <8051.h>
 
 #include "include/delay.h"
+#include "include/timer.h"
 
-void timer_clear(void) {
-    TR0 = 0;
-    TF0 = 0;
-}
-
-void timer_mode_1(int value) {
-    timer_clear();
-    TMOD = 0x01;
-    TH0 = (unsigned char)(value >> 8);
-    TL0 = (unsigned char)value;
-    TR0 = 1;
-}
-
+// One millisecond in ticks is determined as follows:
+//   9.2 MHz is the clock rate
+//   The timer divider is 12
+//   The timer rate is 12 / 9.2 MHz = 1.304 us
+//   The ticks are 1000 ms / (1.304 us) = 766.667
+//   65536 - 766.667 = 64769.33
 void delay_ms(int ms) {
     for (int i = 0; i < ms; i++) {
-        // One millisecond in ticks is determined as follows:
-        //   9.2 MHz is the clock rate
-        //   The timer divider is 12
-        //   The timer rate is 12 / 9.2 MHz = 1.304 us
-        //   The ticks are 1000 ms / (1.304 us) = 766.667
-        //   65536 - 766.667 = 64769.33
         timer_mode_1(64769);
-        while (TF0 == 0) {}
-        timer_clear();
+        timer_wait();
+        timer_stop();
     }
 }

src/gpio.c

@@ -1,3 +1,5 @@
+#include <stdio.h>
+
 #include "include/gpio.h"
 
 void gpio_init() {
@@ -98,3 +100,22 @@ void gpio_init() {
     GPCRJ6 = 0x44;
     GPCRJ7 = 0x80;
 }
+
+void gpio_debug_bank(char bank, unsigned char data) {
+    for(char i = 0; i < 8; i++) {
+        printf("%c%d = %d\n", bank, i, (data >> i) & 1);
+    }
+}
+
+void gpio_debug(void) {
+    gpio_debug_bank('A', GPDRA);
+    gpio_debug_bank('B', GPDRB);
+    gpio_debug_bank('C', GPDRC);
+    gpio_debug_bank('D', GPDRD);
+    gpio_debug_bank('E', GPDRE);
+    gpio_debug_bank('F', GPDRF);
+    gpio_debug_bank('G', GPDRG);
+    gpio_debug_bank('H', GPDRH);
+    gpio_debug_bank('I', GPDRI);
+    gpio_debug_bank('J', GPDRJ);
+}

src/include/gpio.h

@@ -2,6 +2,7 @@
 #define _GPIO_H_
 
 void gpio_init(void);
+void gpio_debug(void);
 
 __xdata volatile unsigned char __at(0x1600) GCR;
 

src/include/timer.h

@@ -0,0 +1,8 @@
+#ifndef _TIMER_H_
+#define _TIMER_H_
+
+void timer_mode_1(int value);
+void timer_wait(void);
+void timer_stop(void);
+
+#endif // _TIMER_H_

src/main.c

@@ -19,6 +19,8 @@ struct Pin LED_AIRPLANE_N = PIN(G, 6);
 
 struct Pin PWR_SW = PIN(D, 0);
 
+static char * MODEL = "galp3-c";
+
 void main() {
     gpio_init();
     gctrl_init();
@@ -29,10 +31,10 @@ void main() {
     //TODO: INTC, PECI, PWM, SMBUS
 
     // Set the battery full LED (to know our firmware is loaded)
-    pin_set(&LED_BAT_CHG, true);
-    delay_ms(1000);
     pin_set(&LED_BAT_FULL, true);
-    printf("Hello from System76 EC!\n");
+    printf("Hello from System76 EC for %s!\n", MODEL);
+
+    gpio_debug();
 
     bool last = false;
     for(;;) {

src/stdio.c

@@ -1,20 +1,31 @@
 #include <stdio.h>
 
-#include "include/delay.h"
 #include "include/kbscan.h"
+#include "include/timer.h"
 
+// Wait 25 us
+// 65536 - (25 / 1.304) = 65517
+void parallel_delay(void) {
+    timer_mode_1(65517);
+    timer_wait();
+    timer_stop();
+}
+
+// This takes a time of 25 us * 3 = 75 us
+// That produces a frequency of 13.333 KHz
+// Which produces a bitrate of 106.667 KHz
 void parallel_write(unsigned char value) {
     // Make sure clock is high
     KSOH1 = 0xFF;
-    delay_ms(1);
+    parallel_delay();
 
     // Set value
     KSOL = value;
-    delay_ms(1);
+    parallel_delay();
 
     // Set clock low
     KSOH1 = 0;
-    delay_ms(1);
+    parallel_delay();
 
     // Set clock high again
     KSOH1 = 0xFF;

src/timer.c

@@ -0,0 +1,20 @@
+#include <8051.h>
+
+#include "include/timer.h"
+
+void timer_mode_1(int value) {
+    timer_stop();
+    TMOD = 0x01;
+    TH0 = (unsigned char)(value >> 8);
+    TL0 = (unsigned char)value;
+    TR0 = 1;
+}
+
+void timer_wait(void) {
+    while (TF0 == 0) {}
+}
+
+void timer_stop(void) {
+    TR0 = 0;
+    TF0 = 0;
+}