src-avr: Add 'sleep_cpu' to reduce power usage while idle

Signed-off-by: Keith Packard <keithp@keithp.com>

diff --git a/src-avr/ao_task.c b/src-avr/ao_task.c
index 83f12e2b2fa3b2fbea5943d878757b0d444fa8cd..514671334ec4903da97fdc3c4ef760dd28039948 100644 (file)
--- a/src-avr/ao_task.c
+++ b/src-avr/ao_task.c
@@ -102,19 +102,6 @@ ao_add_task(__xdata struct ao_task * task, void (*start)(void), __code char *nam
        ao_init_stack(task, start);
 }
 
-void
-ao_show_task_from(void)
-{
-//     if (ao_cur_task)
-//             printf("switching from %s\n", ao_cur_task->name);
-}
-
-void
-ao_show_task_to(void)
-{
-//     printf("switching to %s\n", ao_cur_task->name);
-}
-
 /* Task switching function. This must not use any stack variables */
 void
 ao_yield(void) __naked
@@ -187,7 +174,6 @@ ao_yield(void) __naked
        SP = AO_STACK_START - 1;
 #endif
 
-       ao_show_task_from();
        /* Find a task to run. If there isn't any runnable task,
         * this loop will run forever, which is just fine
         */
@@ -211,10 +197,11 @@ ao_yield(void) __naked
                                break;
                        }
 
-#ifdef AVR
-#else
                        /* Enter lower power mode when there isn't anything to do */
                        if (ao_next_task_index == ao_cur_task_index)
+#ifdef AVR
+                               sleep_cpu();
+#else
                                PCON = PCON_IDLE;
 #endif
                }
@@ -225,7 +212,6 @@ ao_yield(void) __naked
                uint8_t sp_l, sp_h;
                sp_l = (uint16_t) ao_cur_task->sp;
                sp_h = ((uint16_t) ao_cur_task->sp) >> 8;
-               ao_show_task_to();
                cli();
                asm("out __SP_H__,%0" : : "r" (sp_h) );
                asm("out __SP_L__,%0" : : "r" (sp_l) );
@@ -291,9 +277,11 @@ ao_yield(void) __naked
 uint8_t
 ao_sleep(__xdata void *wchan)
 {
+       cli();
        __critical {
                ao_cur_task->wchan = wchan;
        }
+       sei();
        ao_yield();
        ao_cur_task->alarm = 0;
        if (ao_cur_task->wchan) {

diff --git a/src-avr/ao_timer.c b/src-avr/ao_timer.c
index cc48dd2a39ff07ae8209d0459eb81baabaaf4723..f0918a7d68da066064725937bf5893df65778844 100644 (file)
--- a/src-avr/ao_timer.c
+++ b/src-avr/ao_timer.c
@@ -162,6 +162,9 @@ ao_clock_init(void)
        PLLCSR |= (1 << PLLE);
        while (!(PLLCSR & (1 << PLOCK)))
                ;
+
+       set_sleep_mode(SLEEP_MODE_IDLE);
+       sleep_enable();
 #else
        /* Switch system clock to crystal oscilator */
        CLKCON = (CLKCON & ~CLKCON_OSC_MASK) | (CLKCON_OSC_XTAL);

diff --git a/src-avr/avr.h b/src-avr/avr.h
index 8c9c7bd70eaeac0c0ce465d5cba50e25ec31c34c..9811a07f64edcc46f66edad244839b581d5abc18 100644 (file)
--- a/src-avr/avr.h
+++ b/src-avr/avr.h
@@ -21,6 +21,7 @@
 #include <stdio.h>
 #include <avr/io.h>
 #include <avr/interrupt.h>
+#include <avr/sleep.h>
 
 #if TEENSY
 #define F_CPU 16000000UL       // 16 MHz