From: Keith Packard Date: Thu, 29 Aug 2013 04:12:25 +0000 (-0600) Subject: altos/stm: Make sure we switch to MSI during timer init X-Git-Tag: 1.2.9.4~119 X-Git-Url: https://git.gag.com/?p=fw%2Faltos;a=commitdiff_plain;h=7c82acc1c1c5b7b4da7c7ecb3b2fd90140e4c703 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 --- 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 */