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efm32 cmu: convenience functions

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includes a fix for the register definitions (subtle differences between
two fields)
This commit is contained in:
chrysn 2012-03-04 16:59:20 +01:00
parent 61b649370f
commit e1a660eb9d
3 changed files with 144 additions and 10 deletions
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63
include/libopencm3/efm32/tinygecko/cmu.convenienceheaders
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@ -0,0 +1,63 @@
/** CMU convenience functions
*
* These functions assist in clock switching, and are intended to be safer to
* use than direct fiddling with registers. They try to be suitable for typical
* applications, and will invest some bytes of code in order to minimize power
* consumption.
*
* @todo Work on this module is stalled until I can figure out if there is a
* way to have a cmu_shutdown_unused function at all.
*
* @defgroup EFM32TG_CMU_convenience CMU convenience functions
* @{
*/
/** Disable all oscillators not currently in use.
*
* The implementation follows d0034_efm32tg_reference_manual.pdf figure 11.1.
* The clock out pin configurations are not depicted there, but described in
* section 11.3.4.
*
* @todo This function is ignorant of ongoing calibrations.
*
* @todo This doesn't work at all: Fields like HFCLKSEL are write-only.
* */
static void cmu_shutdown_unused(void)
{
/* Is HFXO needed? */
if (!(
(CMU_CMD & CMU_CMD_HFCLKSEL_MASK) == CMU_CMD_HFCLKSEL_HFXO ||
(
(CMU_CTRL & CMU_CTRL_CLKOUTSEL1_MASK) == CMU_CTRL_CLKOUTSEL1_HFXOQ &&
(CMU_ROUTE & CMU_ROUTE_CLKOUT1PEN)
) || (
(CMU_CTRL & CMU_CTRL_CLKOUTSEL0_MASK) == CMU_CTRL_CLKOUTSEL0_HFXO &&
(CMU_ROUTE & CMU_ROUTE_CLKOUT0PEN)
)))
CMU_OSCENCMD = CMU_OSCENCMD_HFXODIS;
/* Is HFRCO neede? */
if (!(
(CMU_CMD & CMU_CMD_HFCLKSEL_MASK) == CMU_CMD_HFCLKSEL_HFRCO ||
(
(CMU_CTRL & CMU_CTRL_CLKOUTSEL1_MASK) == CMU_CTRL_CLKOUTSEL1_HFRCOQ &&
(CMU_ROUTE & CMU_ROUTE_CLKOUT1PEN)
) || (
(CMU_CTRL & CMU_CTRL_CLKOUTSEL0_MASK) == CMU_CTRL_CLKOUTSEL0_HFRCO &&
(CMU_ROUTE & CMU_ROUTE_CLKOUT0PEN)
)))
{}
// CMU_OSCENCMD = CMU_OSCENCMD_HFRCODIS;
}
/** Switch HFCLK to LFRC. This call is not only blocking, but even freezes
* everything depending on HFCLK until LFRC is stable. The procedure is
* sketched in d0034_efm32tg_reference_manual.pdf figure 11.2. */
static void cmu_hfclk_switch_blocking(void)
{
CMU_OSCENCMD = CMU_OSCENCMD_LFRCOEN;
CMU_CMD = CMU_CMD_HFCLKSEL_LFRCO;
CMU_OSCENCMD = CMU_OSCENCMD_HFRCODIS;
}
/** @} */

79
include/libopencm3/efm32/tinygecko/cmu.h
View File

@ -100,14 +100,14 @@
#define CMU_CTRL_CLKOUTSEL1_HFRCOQ (6<<23)
#define CMU_CTRL_CLKOUTSEL1_AUXHFRCOQ (7<<23)
#define CMU_CTRL_CLKOUTSEL1_MASK (0x7<<23)
#define CMU_CTRL_CLKOUTSEL0_LFRCO (0<<20)
#define CMU_CTRL_CLKOUTSEL0_LFXO (1<<20)
#define CMU_CTRL_CLKOUTSEL0_HFCLK (2<<20)
#define CMU_CTRL_CLKOUTSEL0_LFXOQ (3<<20)
#define CMU_CTRL_CLKOUTSEL0_HFXOQ (4<<20)
#define CMU_CTRL_CLKOUTSEL0_LFRCOQ (5<<20)
#define CMU_CTRL_CLKOUTSEL0_HFRCOQ (6<<20)
#define CMU_CTRL_CLKOUTSEL0_AUXHFRCOQ (7<<20)
#define CMU_CTRL_CLKOUTSEL0_HFRCO (0<<20)
#define CMU_CTRL_CLKOUTSEL0_HFXO (1<<20)
#define CMU_CTRL_CLKOUTSEL0_HFCLK2 (2<<20)
#define CMU_CTRL_CLKOUTSEL0_HFCLK4 (3<<20)
#define CMU_CTRL_CLKOUTSEL0_HFCLK8 (4<<20)
#define CMU_CTRL_CLKOUTSEL0_HFCLK16 (5<<20)
#define CMU_CTRL_CLKOUTSEL0_ULFRCO (6<<20)
#define CMU_CTRL_CLKOUTSEL0_AUXHFRCO (7<<20)
#define CMU_CTRL_CLKOUTSEL0_MASK (0x7<<20)
#define CMU_CTRL_LFXOTIMEOUT_8CYCLES (0<<18)
#define CMU_CTRL_LFXOTIMEOUT_1KCYCLES (1<<18)
@ -580,6 +580,69 @@
/** @} */
/** CMU convenience functions
*
* These functions assist in clock switching, and are intended to be safer to
* use than direct fiddling with registers. They try to be suitable for typical
* applications, and will invest some bytes of code in order to minimize power
* consumption.
*
* @todo Work on this module is stalled until I can figure out if there is a
* way to have a cmu_shutdown_unused function at all.
*
* @defgroup EFM32TG_CMU_convenience CMU convenience functions
* @{
*/
/** Disable all oscillators not currently in use.
*
* The implementation follows d0034_efm32tg_reference_manual.pdf figure 11.1.
* The clock out pin configurations are not depicted there, but described in
* section 11.3.4.
*
* @todo This function is ignorant of ongoing calibrations.
*
* @todo This doesn't work at all: Fields like HFCLKSEL are write-only.
* */
static void cmu_shutdown_unused(void)
{
/* Is HFXO needed? */
if (!(
(CMU_CMD & CMU_CMD_HFCLKSEL_MASK) == CMU_CMD_HFCLKSEL_HFXO ||
(
(CMU_CTRL & CMU_CTRL_CLKOUTSEL1_MASK) == CMU_CTRL_CLKOUTSEL1_HFXOQ &&
(CMU_ROUTE & CMU_ROUTE_CLKOUT1PEN)
) || (
(CMU_CTRL & CMU_CTRL_CLKOUTSEL0_MASK) == CMU_CTRL_CLKOUTSEL0_HFXO &&
(CMU_ROUTE & CMU_ROUTE_CLKOUT0PEN)
)))
CMU_OSCENCMD = CMU_OSCENCMD_HFXODIS;
/* Is HFRCO neede? */
if (!(
(CMU_CMD & CMU_CMD_HFCLKSEL_MASK) == CMU_CMD_HFCLKSEL_HFRCO ||
(
(CMU_CTRL & CMU_CTRL_CLKOUTSEL1_MASK) == CMU_CTRL_CLKOUTSEL1_HFRCOQ &&
(CMU_ROUTE & CMU_ROUTE_CLKOUT1PEN)
) || (
(CMU_CTRL & CMU_CTRL_CLKOUTSEL0_MASK) == CMU_CTRL_CLKOUTSEL0_HFRCO &&
(CMU_ROUTE & CMU_ROUTE_CLKOUT0PEN)
)))
{}
// CMU_OSCENCMD = CMU_OSCENCMD_HFRCODIS;
}
/** Switch HFCLK to LFRC. This call is not only blocking, but even freezes
* everything depending on HFCLK until LFRC is stable. The procedure is
* sketched in d0034_efm32tg_reference_manual.pdf figure 11.2. */
static void cmu_hfclk_switch_blocking(void)
{
CMU_OSCENCMD = CMU_OSCENCMD_LFRCOEN;
CMU_CMD = CMU_CMD_HFCLKSEL_LFRCO;
CMU_OSCENCMD = CMU_OSCENCMD_HFRCODIS;
}
/** @} */
/** @} */

12
include/libopencm3/efm32/tinygecko/cmu.yaml
View File

@ -19,7 +19,7 @@ registers:
- name: CLKOUTSEL1
shift: 23
length: 3
values: &CLKOUTSEL1_values
values:
- {name: LFRCO, value: 0}
- {name: LFXO, value: 1}
- {name: HFCLK, value: 2}
@ -31,7 +31,15 @@ registers:
- name: CLKOUTSEL0
shift: 20
length: 3
values: *CLKOUTSEL1_values
values:
- {name: HFRCO, value: 0}
- {name: HFXO, value: 1}
- {name: HFCLK2, value: 2}
- {name: HFCLK4, value: 3}
- {name: HFCLK8, value: 4}
- {name: HFCLK16, value: 5}
- {name: ULFRCO, value: 6}
- {name: AUXHFRCO, value: 7}
- name: LFXOTIMEOUT
shift: 18
length: 2