From c0d62add7e20301c80e829924dd523f6390c1f32 Mon Sep 17 00:00:00 2001
From: David Lamparter <equinox@diac24.net>
Date: Sun, 7 Dec 2014 16:45:48 +0100
Subject: tick: support 1Hz/100Hz

---
 tick.c | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/tick.c b/tick.c
index a99b303..c83cc42 100644
--- a/tick.c
+++ b/tick.c
@@ -5,10 +5,23 @@ static union {
 	uint8_t u8[4];
 } systick = { .u32 = 0 };
 
+#ifndef SYSTICK_USER_1HZ
+#define systick_user_1hz()
+#endif
+
+static uint8_t tick_sub;
+
 ISR(TIMER1_COMPA_vect)
 {
+#ifdef SYSTICK_USER_100HZ
+	systick_user_100hz();
+	if (++tick_sub < 100)
+		return;
+
+	tick_sub = 0;
+#endif
 	systick.u32++;
-//	dbg_dump_ret();
+	systick_user_1hz();
 }
 
 static void uart_puttick(void)
@@ -21,7 +34,11 @@ static void uart_puttick(void)
 	uart_puthex(systick.u8[1]);
 	uart_puthex(systick.u8[0]);
 	_uart_putch('.');
+#ifdef SYSTICK_USER_100HZ
+	uart_puthex(tick_sub);
+#else
 	uart_puthex16(frac);
+#endif
 #if DEBUG_SP
 	_uart_putch('~');
 	uint8_t spl, sph;
@@ -38,10 +55,17 @@ static void uart_puttick(void)
 static void tick_init(void)
 {
 	TCCR1A = 0;
+#ifdef SYSTICK_USER_100HZ
+	TCCR1B = (1 << WGM12) | (0 << CS12) | (1 << CS11) | (0 << CS10); // 8 MHz / 8 = 1 MHz
+	asm volatile ("" ::: "memory");
+	TCNT1 = 0;
+	OCR1A = 9999; // 100 Hz
+#else
 	TCCR1B = (1 << WGM12) | (1 << CS12) | (0 << CS11) | (0 << CS10); // 8 MHz / 256 = 31250 Hz
 	asm volatile ("" ::: "memory");
 	TCNT1 = 0;
 	OCR1A = 31249; // 1 Hz
+#endif
 	asm volatile ("" ::: "memory");
 	TIFR1 = (1 << OCF1A);
 	TIMSK1 = (1 << OCIE1A);
-- 
cgit v1.2.1