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cc2538: lpm: Let system clock transitions complete before further changes

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As a matter of precaution, always make sure that pending system clock
transitions are complete before requesting a new change of the system clock
source.

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
This commit is contained in:
Benoît Thébaudeau 2013-12-03 18:51:39 +01:00
parent 8514a91ea9
commit 13006e1c73
1 changed files with 3 additions and 0 deletions
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3
cpu/cc2538/lpm.c
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@ -158,6 +158,9 @@ enter_pm0(void)
static void static void
select_32_mhz_xosc(void) select_32_mhz_xosc(void)
{ {
/*First, make sure there is no ongoing clock source change */
while((REG(SYS_CTRL_CLOCK_STA) & SYS_CTRL_CLOCK_STA_SOURCE_CHANGE) != 0);
/* Turn on the 32 MHz XOSC and source the system clock on it. */ /* Turn on the 32 MHz XOSC and source the system clock on it. */
REG(SYS_CTRL_CLOCK_CTRL) &= ~SYS_CTRL_CLOCK_CTRL_OSC; REG(SYS_CTRL_CLOCK_CTRL) &= ~SYS_CTRL_CLOCK_CTRL_OSC;