diff options
author | Bdale Garbee <bdale@gag.com> | 2012-09-12 20:01:22 -0600 |
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committer | Bdale Garbee <bdale@gag.com> | 2012-09-12 20:01:22 -0600 |
commit | 3b612efcd1dddc6a3d59012f7ed57754b1f798c2 (patch) | |
tree | 18d50713491ef96c5c127a309f870efb6c33f98d /src/avr/ao_clock.c | |
parent | e076773c1693e2a62bb828dee71c04c20dbab0a5 (diff) | |
parent | 01eb36408d7e0e826b431fcc1d3b2deb23607e0b (diff) |
Merge branch 'new-debian' into debian
Conflicts:
ChangeLog
debian/altos.install
debian/changelog
debian/control
debian/copyright
debian/dirs
debian/docs
debian/menu
debian/rules
src/Makefile
Diffstat (limited to 'src/avr/ao_clock.c')
-rw-r--r-- | src/avr/ao_clock.c | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/src/avr/ao_clock.c b/src/avr/ao_clock.c new file mode 100644 index 00000000..0d42b6d5 --- /dev/null +++ b/src/avr/ao_clock.c @@ -0,0 +1,77 @@ +/* + * Copyright © 2011 Keith Packard <keithp@keithp.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; version 2 of the License. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. + */ + +#include "ao.h" + +/* + * AltOS always cranks the clock to the max frequency + */ + +void +ao_clock_init(void) +{ + /* disable RC clock */ + CLKSEL0 &= ~(1 << RCE); + + /* Disable PLL */ + PLLCSR &= ~(1 << PLLE); + + /* Enable external clock */ + CLKSEL0 |= (1 << EXTE); + + /* wait for external clock to be ready */ + while ((CLKSTA & (1 << EXTON)) == 0) + ; + + /* select external clock */ + CLKSEL0 |= (1 << CLKS); + + /* Disable the clock prescaler */ + cli(); + CLKPR = (1 << CLKPCE); + + /* Always run the system clock at 8MHz */ +#if AVR_CLOCK > 12000000UL + CLKPR = 1; +#else + CLKPR = 0; +#endif + sei(); + + /* Set up the PLL to use the crystal */ + + /* Use primary system clock as PLL source */ + PLLFRQ = ((0 << PINMUX) | /* Use primary clock */ + (0 << PLLUSB) | /* No divide by 2 for USB */ + (0 << PLLTM0) | /* Disable high speed timer */ + (0x4 << PDIV0)); /* 48MHz PLL clock */ + + /* Set the frequency of the crystal */ +#if AVR_CLOCK > 12000000UL + PLLCSR |= (1 << PINDIV); /* For 16MHz crystal on Teensy board */ +#else + PLLCSR &= ~(1 << PINDIV); /* For 8MHz crystal on TeleScience board */ +#endif + + /* Enable the PLL */ + PLLCSR |= (1 << PLLE); + while (!(PLLCSR & (1 << PLOCK))) + ; + + set_sleep_mode(SLEEP_MODE_IDLE); + sleep_enable(); +} |