115 строки
2,8 КиБ
Go
115 строки
2,8 КиБ
Go
//go:build stm32 && stm32f7x2
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// +build stm32,stm32f7x2
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package runtime
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import (
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"device/stm32"
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"machine"
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)
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/*
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clock settings
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+-------------+--------+
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| HSE | 8mhz |
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| SYSCLK | 216mhz |
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| HCLK | 216mhz |
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| APB1(PCLK1) | 27mhz |
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| APB2(PCLK2) | 108mhz |
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+-------------+--------+
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*/
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const (
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HSE_STARTUP_TIMEOUT = 0x0500
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PLL_M = 4
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PLL_N = 216
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PLL_P = 2
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PLL_Q = 2
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)
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func init() {
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initCLK()
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machine.InitSerial()
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initTickTimer(&machine.TIM3)
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}
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func putchar(c byte) {
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machine.Serial.WriteByte(c)
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}
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func getchar() byte {
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for machine.Serial.Buffered() == 0 {
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Gosched()
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}
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v, _ := machine.Serial.ReadByte()
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return v
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}
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func buffered() int {
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return machine.Serial.Buffered()
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}
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func initCLK() {
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// PWR_CLK_ENABLE
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stm32.RCC.APB1ENR.SetBits(stm32.RCC_APB1ENR_PWREN)
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_ = stm32.RCC.APB1ENR.Get()
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// PWR_VOLTAGESCALING_CONFIG
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stm32.PWR.CR1.ReplaceBits(0x3<<stm32.PWR_CR1_VOS_Pos, stm32.PWR_CR1_VOS_Msk, 0)
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_ = stm32.PWR.CR1.Get()
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// Initialize the High-Speed External Oscillator
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initOsc()
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// Set flash wait states (min 7 latency units) based on clock
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if (stm32.FLASH.ACR.Get() & stm32.FLASH_ACR_LATENCY_Msk) < 7 {
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stm32.FLASH.ACR.ReplaceBits(7, stm32.FLASH_ACR_LATENCY_Msk, 0)
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}
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// HCLK (0x1C00 = DIV_16, 0x0 = RCC_SYSCLK_DIV1) - ensure timers remain
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// within spec as the SYSCLK source changes.
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stm32.RCC.CFGR.ReplaceBits(0x00001C00, stm32.RCC_CFGR_PPRE1_Msk, 0)
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stm32.RCC.CFGR.ReplaceBits(0x00001C00<<3, stm32.RCC_CFGR_PPRE2_Msk, 0)
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stm32.RCC.CFGR.ReplaceBits(0, stm32.RCC_CFGR_HPRE_Msk, 0)
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// Set SYSCLK source and wait
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// (2 = PLLCLK, 3 = RCC_CFGR_SW mask, 3 << 3 = RCC_CFGR_SWS mask)
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stm32.RCC.CFGR.ReplaceBits(2, 3, 0)
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for stm32.RCC.CFGR.Get()&(3<<2) != (2 << 2) {
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}
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// Set flash wait states (max 7 latency units) based on clock
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if (stm32.FLASH.ACR.Get() & stm32.FLASH_ACR_LATENCY_Msk) > 7 {
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stm32.FLASH.ACR.ReplaceBits(7, stm32.FLASH_ACR_LATENCY_Msk, 0)
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}
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// Set APB1 and APB2 clocks (0x1800 = DIV8, 0x1000 = DIV2)
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stm32.RCC.CFGR.ReplaceBits(0x1800, stm32.RCC_CFGR_PPRE1_Msk, 0)
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stm32.RCC.CFGR.ReplaceBits(0x1000<<3, stm32.RCC_CFGR_PPRE2_Msk, 0)
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}
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func initOsc() {
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// Enable HSE, wait until ready
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stm32.RCC.CR.SetBits(stm32.RCC_CR_HSEON)
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for !stm32.RCC.CR.HasBits(stm32.RCC_CR_HSERDY) {
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}
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// Disable the PLL, wait until disabled
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stm32.RCC.CR.ClearBits(stm32.RCC_CR_PLLON)
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for stm32.RCC.CR.HasBits(stm32.RCC_CR_PLLRDY) {
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}
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// Configure the PLL
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stm32.RCC.PLLCFGR.Set(0x20000000 |
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(1 << stm32.RCC_PLLCFGR_PLLSRC_Pos) | // 1 = HSE
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PLL_M |
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(PLL_N << stm32.RCC_PLLCFGR_PLLN_Pos) |
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(((PLL_P >> 1) - 1) << stm32.RCC_PLLCFGR_PLLP_Pos) |
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(PLL_Q << stm32.RCC_PLLCFGR_PLLQ_Pos))
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// Enable the PLL, wait until ready
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stm32.RCC.CR.SetBits(stm32.RCC_CR_PLLON)
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for !stm32.RCC.CR.HasBits(stm32.RCC_CR_PLLRDY) {
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}
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}
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