diff options
| author | Keith Packard <keithp@keithp.com> | 2013-08-28 22:12:25 -0600 |
|---|---|---|
| committer | Keith Packard <keithp@keithp.com> | 2013-08-28 22:12:25 -0600 |
| commit | 7c82acc1c1c5b7b4da7c7ecb3b2fd90140e4c703 (patch) | |
| tree | eb9f6713349af3d2ed3f55550664c58df379a2fc /src/stm/ao_timer.c | |
| parent | 6802b6a65b1fec06c2c873282be792c40b3c8f5e (diff) | |
altos/stm: Make sure we switch to MSI during timer init
Need to ensure that the CPU is actually using the MSI during timer
init or all of the other clock changes won't work
Signed-off-by: Keith Packard <keithp@keithp.com>
Diffstat (limited to 'src/stm/ao_timer.c')
| -rw-r--r-- | src/stm/ao_timer.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/src/stm/ao_timer.c b/src/stm/ao_timer.c index 5cf1e4a8..34f9edb9 100644 --- a/src/stm/ao_timer.c +++ b/src/stm/ao_timer.c @@ -90,7 +90,15 @@ ao_clock_init(void) /* Switch to MSI while messing about */ stm_rcc.cr |= (1 << STM_RCC_CR_MSION); while (!(stm_rcc.cr & (1 << STM_RCC_CR_MSIRDY))) - asm("nop"); + ao_arch_nop(); + + stm_rcc.cfgr = (stm_rcc.cfgr & ~(STM_RCC_CFGR_SW_MASK << STM_RCC_CFGR_SW)) | + (STM_RCC_CFGR_SW_MSI << STM_RCC_CFGR_SW); + + /* wait for system to switch to MSI */ + while ((stm_rcc.cfgr & (STM_RCC_CFGR_SWS_MASK << STM_RCC_CFGR_SWS)) != + (STM_RCC_CFGR_SWS_MSI << STM_RCC_CFGR_SWS)) + ao_arch_nop(); /* reset SW, HPRE, PPRE1, PPRE2, MCOSEL and MCOPRE */ stm_rcc.cfgr &= (uint32_t)0x88FFC00C; @@ -141,7 +149,6 @@ ao_clock_init(void) stm_flash.acr |= (1 << STM_FLASH_ACR_PRFEN); /* Enable 1 wait state so the CPU can run at 32MHz */ - /* (haven't managed to run the CPU at 32MHz yet, it's at 16MHz) */ stm_flash.acr |= (1 << STM_FLASH_ACR_LATENCY); /* Enable power interface clock */ |