diff options
| author | Keith Packard <keithp@keithp.com> | 2016-03-24 19:28:16 -0600 |
|---|---|---|
| committer | Keith Packard <keithp@keithp.com> | 2016-03-26 16:07:20 -0700 |
| commit | b31c6fd153825ae5ad0fcea7189472af1a9cffff (patch) | |
| tree | a2bbc34816f6f33b3287caf86b1dfa9841d76dd9 /src/lpc/ao_timer_lpc.c | |
| parent | a86d98b708d84c6e0b85cb950e3f1ee16cfc56f5 (diff) | |
altos/lpc: Add fast timer
This offers a faster timer callback for higher-precision operation
Signed-off-by: Keith Packard <keithp@keithp.com>
Diffstat (limited to 'src/lpc/ao_timer_lpc.c')
| -rw-r--r-- | src/lpc/ao_timer_lpc.c | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/src/lpc/ao_timer_lpc.c b/src/lpc/ao_timer_lpc.c index 44fb410e..623559eb 100644 --- a/src/lpc/ao_timer_lpc.c +++ b/src/lpc/ao_timer_lpc.c @@ -99,7 +99,7 @@ ao_clock_init(void) (1 << LPC_SCB_SYSAHBCLKCTRL_FLASHARRAY) | (1 << LPC_SCB_SYSAHBCLKCTRL_GPIO) | (1 << LPC_SCB_SYSAHBCLKCTRL_IOCON)); - + /* Enable the brown-out detection at the highest voltage to * make sure the flash part remains happy */ @@ -112,21 +112,21 @@ ao_clock_init(void) /* Turn the IRC clock back on */ lpc_scb.pdruncfg &= ~(1 << LPC_SCB_PDRUNCFG_IRC_PD); ao_clock_delay(); - + /* Switch to the IRC clock */ lpc_scb.mainclksel = LPC_SCB_MAINCLKSEL_SEL_IRC << LPC_SCB_MAINCLKSEL_SEL; lpc_scb.mainclkuen = (0 << LPC_SCB_MAINCLKUEN_ENA); lpc_scb.mainclkuen = (1 << LPC_SCB_MAINCLKUEN_ENA); while (!(lpc_scb.mainclkuen & (1 << LPC_SCB_MAINCLKUEN_ENA))) ; - + /* Switch USB to the main clock */ lpc_scb.usbclksel = (LPC_SCB_USBCLKSEL_SEL_MAIN_CLOCK << LPC_SCB_USBCLKSEL_SEL); lpc_scb.usbclkuen = (0 << LPC_SCB_USBCLKUEN_ENA); lpc_scb.usbclkuen = (1 << LPC_SCB_USBCLKUEN_ENA); while (!(lpc_scb.usbclkuen & (1 << LPC_SCB_USBCLKUEN_ENA))) ; - + /* Find a PLL post divider ratio that gets the FCCO in range */ for (p = 0; p < 4; p++) if (AO_LPC_CLKOUT << (1 + p) >= AO_LPC_FCCO_MIN) @@ -163,12 +163,12 @@ ao_clock_init(void) lpc_scb.syspllclkuen = (1 << LPC_SCB_SYSPLLCLKUEN_ENA); while (!(lpc_scb.syspllclkuen & (1 << LPC_SCB_SYSPLLCLKUEN_ENA))) ; - + /* Turn on the PLL */ lpc_scb.pdruncfg &= ~(1 << LPC_SCB_PDRUNCFG_SYSPLL_PD); /* Wait for it to lock */ - + for (i = 0; i < 20000; i++) if (lpc_scb.syspllstat & (1 << LPC_SCB_SYSPLLSTAT_LOCK)) break; @@ -199,7 +199,7 @@ ao_clock_init(void) lpc_scb.usbpllclkuen = (1 << LPC_SCB_USBPLLCLKUEN_ENA); while (!(lpc_scb.usbpllclkuen & (1 << LPC_SCB_USBPLLCLKUEN_ENA))) ; - + /* Power down everything we don't need */ lpc_scb.pdruncfg = ((1 << LPC_SCB_PDRUNCFG_IRCOUT_PD) | (1 << LPC_SCB_PDRUNCFG_IRC_PD) | |