154c7c691b
This commit changes the number of wait states for the stm32f103 chip to 2 instead of 4. This gets it back in line with the datasheet, but it also has the side effect of breaking I2C. Therefore, another (seemingly unrelated) change is needed: the i2cTimeout constant must be increased to a higher value to adjust to the lower flash wait states - presumably because the lower number of wait states allows the chip to run code faster.
123 строки
3,7 КиБ
Go
123 строки
3,7 КиБ
Go
// +build stm32f407
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package machine
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// Peripheral abstraction layer for the stm32f407
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import (
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"device/stm32"
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"runtime/interrupt"
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)
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func CPUFrequency() uint32 {
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return 168000000
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}
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// Alternative peripheral pin functions
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const (
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AF0_SYSTEM = 0
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AF1_TIM1_2 = 1
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AF2_TIM3_4_5 = 2
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AF3_TIM8_9_10_11 = 3
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AF4_I2C1_2_3 = 4
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AF5_SPI1_SPI2 = 5
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AF6_SPI3 = 6
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AF7_USART1_2_3 = 7
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AF8_USART4_5_6 = 8
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AF9_CAN1_CAN2_TIM12_13_14 = 9
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AF10_OTG_FS_OTG_HS = 10
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AF11_ETH = 11
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AF12_FSMC_SDIO_OTG_HS_1 = 12
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AF13_DCMI = 13
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AF14 = 14
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AF15_EVENTOUT = 15
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)
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//---------- UART related types and code
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// UART representation
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type UART struct {
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Buffer *RingBuffer
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Bus *stm32.USART_Type
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Interrupt interrupt.Interrupt
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AltFuncSelector uint8
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}
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// Configure the UART.
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func (uart UART) configurePins(config UARTConfig) {
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// enable the alternate functions on the TX and RX pins
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config.TX.ConfigureAltFunc(PinConfig{Mode: PinModeUARTTX}, uart.AltFuncSelector)
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config.RX.ConfigureAltFunc(PinConfig{Mode: PinModeUARTRX}, uart.AltFuncSelector)
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}
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// UART baudrate calc based on the bus and clockspeed
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// NOTE: keep this in sync with the runtime/runtime_stm32f407.go clock init code
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func (uart UART) getBaudRateDivisor(baudRate uint32) uint32 {
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var clock uint32
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switch uart.Bus {
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case stm32.USART1, stm32.USART6:
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clock = CPUFrequency() / 2 // APB2 Frequency
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case stm32.USART2, stm32.USART3, stm32.UART4, stm32.UART5:
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clock = CPUFrequency() / 4 // APB1 Frequency
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}
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return clock / baudRate
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}
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//---------- SPI related types and code
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// SPI on the STM32Fxxx using MODER / alternate function pins
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type SPI struct {
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Bus *stm32.SPI_Type
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AltFuncSelector uint8
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}
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// Set baud rate for SPI
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func (spi SPI) getBaudRate(config SPIConfig) uint32 {
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var conf uint32
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localFrequency := config.Frequency
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if spi.Bus != stm32.SPI1 {
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// Assume it's SPI2 or SPI3 on APB1 at 1/2 the clock frequency of APB2, so
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// we want to pretend to request 2x the baudrate asked for
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localFrequency = localFrequency * 2
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}
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// set frequency dependent on PCLK prescaler. Since these are rather weird
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// speeds due to the CPU freqency, pick a range up to that frquency for
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// clients to use more human-understandable numbers, e.g. nearest 100KHz
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// These are based on APB2 clock frquency (84MHz on the discovery board)
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// TODO: also include the MCU/APB clock setting in the equation
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switch true {
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case localFrequency < 328125:
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conf = stm32.SPI_CR1_BR_Div256
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case localFrequency < 656250:
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conf = stm32.SPI_CR1_BR_Div128
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case localFrequency < 1312500:
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conf = stm32.SPI_CR1_BR_Div64
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case localFrequency < 2625000:
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conf = stm32.SPI_CR1_BR_Div32
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case localFrequency < 5250000:
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conf = stm32.SPI_CR1_BR_Div16
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case localFrequency < 10500000:
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conf = stm32.SPI_CR1_BR_Div8
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// NOTE: many SPI components won't operate reliably (or at all) above 10MHz
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// Check the datasheet of the part
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case localFrequency < 21000000:
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conf = stm32.SPI_CR1_BR_Div4
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case localFrequency < 42000000:
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conf = stm32.SPI_CR1_BR_Div2
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default:
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// None of the specific baudrates were selected; choose the lowest speed
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conf = stm32.SPI_CR1_BR_Div256
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}
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return conf << stm32.SPI_CR1_BR_Pos
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}
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// Configure SPI pins for input output and clock
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func (spi SPI) configurePins(config SPIConfig) {
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config.SCK.ConfigureAltFunc(PinConfig{Mode: PinModeSPICLK}, spi.AltFuncSelector)
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config.SDO.ConfigureAltFunc(PinConfig{Mode: PinModeSPISDO}, spi.AltFuncSelector)
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config.SDI.ConfigureAltFunc(PinConfig{Mode: PinModeSPISDI}, spi.AltFuncSelector)
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}
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