//go:build stm32f7x2

package machine

// Peripheral abstraction layer for the stm32f407

import (
	"device/stm32"
)

func CPUFrequency() uint32 {
	return 216000000
}

// Internal use: configured speed of the APB1 and APB2 timers, this should be kept
// in sync with any changes to runtime package which configures the oscillators
// and clock frequencies
const APB1_TIM_FREQ = 54e6  // 54MHz
const APB2_TIM_FREQ = 216e6 // 216MHz

//---------- UART related code

// Configure the UART.
func (uart *UART) configurePins(config UARTConfig) {
	// enable the alternate functions on the TX and RX pins
	config.TX.ConfigureAltFunc(PinConfig{Mode: PinModeUARTTX}, uart.TxAltFuncSelector)
	config.RX.ConfigureAltFunc(PinConfig{Mode: PinModeUARTRX}, uart.RxAltFuncSelector)
}

// UART baudrate calc based on the bus and clockspeed
// NOTE: keep this in sync with the runtime/runtime_stm32f7x2.go clock init code
func (uart *UART) getBaudRateDivisor(baudRate uint32) uint32 {
	var clock uint32
	switch uart.Bus {
	case stm32.USART1, stm32.USART6:
		clock = CPUFrequency() / 2 // APB2 Frequency
	case stm32.USART2, stm32.USART3, stm32.UART4, stm32.UART5:
		clock = CPUFrequency() / 8 // APB1 Frequency
	}
	return clock / baudRate
}

// Register names vary by ST processor, these are for STM F7x2
func (uart *UART) setRegisters() {
	uart.rxReg = &uart.Bus.RDR
	uart.txReg = &uart.Bus.TDR
	uart.statusReg = &uart.Bus.ISR
	uart.txEmptyFlag = stm32.USART_ISR_TXE
}

//---------- I2C related code

// Gets the value for TIMINGR register
func (i2c *I2C) getFreqRange(br uint32) uint32 {
	// This is a 'magic' value calculated by STM32CubeMX
	// for 27MHz PCLK1 (216MHz CPU Freq / 8).
	// TODO: Do calculations based on PCLK1
	switch br {
	case 10 * KHz:
		return 0x5010C0FF
	case 100 * KHz:
		return 0x00606A9B
	case 400 * KHz:
		return 0x00201625
	case 500 * KHz:
		return 0x00100429
	default:
		return 0
	}
}
