From 91e7807af61ba8a907f7eca8952efcb91ec81935 Mon Sep 17 00:00:00 2001 From: Kevin O'Connor Date: Sun, 5 Jun 2016 10:29:09 -0400 Subject: avr: Add config option to clear the CPU prescaler Some AVR chips ship with a 1/8th clock divisor set. Add a compile time option to manually clear this field at startup. Signed-off-by: Kevin O'Connor --- src/avr/timer.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'src/avr/timer.c') diff --git a/src/avr/timer.c b/src/avr/timer.c index 538f0b19..31f94caf 100644 --- a/src/avr/timer.c +++ b/src/avr/timer.c @@ -5,6 +5,7 @@ // This file may be distributed under the terms of the GNU GPLv3 license. #include // TCNT1 +#include "autoconf.h" // CONFIG_AVR_CLKPR #include "command.h" // shutdown #include "irq.h" // irq_save #include "sched.h" // sched_timer_kick @@ -49,6 +50,14 @@ ISR(TIMER1_COMPA_vect) static void timer_init(void) { + if (CONFIG_AVR_CLKPR != -1 && (uint8_t)CONFIG_AVR_CLKPR != CLKPR) { + // Program the clock prescaler + uint8_t flag = irq_save(); + CLKPR = 0x80; + CLKPR = CONFIG_AVR_CLKPR; + irq_restore(flag); + } + // no outputs TCCR1A = 0; // Normal Mode -- cgit v1.2.3-70-g09d2