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//go:build stm32l0
// +build stm32l0
package runtime
import (
"device/stm32"
"machine"
)
const (
RCC_SYSCLK_DIV1 = 0 // Needs SVD update (should be stm32.RCC_SYSCLK_DIV1)
)
func putchar(c byte) {
machine.Serial.WriteByte(c)
}
func initCLK() {
// Set Power Regulator to enable max performance (1.8V)
stm32.PWR.CR.ReplaceBits(1<<stm32.PWR_CR_VOS_Pos, stm32.PWR_CR_VOS_Msk, 0)
// Calibration (default 0x10)
stm32.RCC.ICSCR.ReplaceBits(0x10<<stm32.RCC_ICSCR_HSI16TRIM_Pos, stm32.RCC_ICSCR_HSI16TRIM_Msk, 0)
// Enable the HSI16 oscillator, since the L0 series boots to the MSI one.
stm32.RCC.CR.ReplaceBits(stm32.RCC_CR_HSI16ON, stm32.RCC_CR_HSI16ON_Msk|stm32.RCC_CR_HSI16DIVEN_Msk, 0)
// Wait for HSI16 to be ready
for !stm32.RCC.CR.HasBits(stm32.RCC_CR_HSI16RDYF) {
}
// Disable PLL
stm32.RCC.CR.ClearBits(stm32.RCC_CR_PLLON)
// Wait for PLL to be disabled
for stm32.RCC.CR.HasBits(stm32.RCC_CR_PLLRDY) {
}
// Configure the PLL to use HSI16 with a PLLDIV of 2 and PLLMUL of 4.
stm32.RCC.CFGR.ReplaceBits(
(stm32.RCC_CFGR_PLLSRC_HSI16<<stm32.RCC_CFGR_PLLSRC_Pos)|
(stm32.RCC_CFGR_PLLMUL_Mul4<<stm32.RCC_CFGR_PLLMUL_Pos)|
(stm32.RCC_CFGR_PLLDIV_Div2<<stm32.RCC_CFGR_PLLDIV_Pos),
stm32.RCC_CFGR_PLLSRC_Msk|
stm32.RCC_CFGR_PLLMUL_Msk|
stm32.RCC_CFGR_PLLDIV_Msk,
0)
// Enable PLL
stm32.RCC.CR.SetBits(stm32.RCC_CR_PLLON)
// Wait for PLL to be ready
for !stm32.RCC.CR.HasBits(stm32.RCC_CR_PLLRDY) {
}
// Adjust flash latency
if FlashLatency > getFlashLatency() {
setFlashLatency(FlashLatency)
for getFlashLatency() != FlashLatency {
}
}
// HCLK
stm32.RCC.CFGR.ReplaceBits(RCC_SYSCLK_DIV1, stm32.RCC_CFGR_HPRE_Msk, 0)
// Use PLL As System clock
stm32.RCC.CFGR.ReplaceBits(stm32.RCC_CFGR_SWS_PLL, stm32.RCC_CFGR_SW_Msk, 0)
for stm32.RCC.CFGR.Get()&stm32.RCC_CFGR_SW_Msk != stm32.RCC_CFGR_SWS_PLL {
}
// Set prescalers so half system clock (PCLKx = HCLK/2)
stm32.RCC.CFGR.SetBits(stm32.RCC_CFGR_PPRE1_Div2 << stm32.RCC_CFGR_PPRE1_Pos)
stm32.RCC.CFGR.SetBits(stm32.RCC_CFGR_PPRE2_Div2 << stm32.RCC_CFGR_PPRE2_Pos)
}
func getFlashLatency() uint32 {
return stm32.FLASH.ACR.Get() & stm32.Flash_ACR_LATENCY_Msk
}
func setFlashLatency(l uint32) {
stm32.FLASH.ACR.ReplaceBits(l, stm32.Flash_ACR_LATENCY_Msk, 0)
}
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