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https://github.com/tinygo-org/tinygo.git
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Ayke van Laethem
887ac286ff
VDDH is typically connected to USB (~5V) or directly to a battery. Measuring the voltage on VDDH is a way to measure the current battery voltage, which in turn can be useful to determine how much power is left in the battery. I've special cased the nrf52840 in a somewhat unusual way, maybe there is a better way, feel free to comment!
117 lines
3.2 KiB
Go
117 lines
3.2 KiB
Go
//go:build nrf52840
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package machine
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import (
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"device/nrf"
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"errors"
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"unsafe"
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)
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// Get peripheral and pin number for this GPIO pin.
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func (p Pin) getPortPin() (*nrf.GPIO_Type, uint32) {
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if p >= 32 {
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return nrf.P1, uint32(p - 32)
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} else {
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return nrf.P0, uint32(p)
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}
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}
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func (uart *UART) setPins(tx, rx Pin) {
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nrf.UART0.PSEL.TXD.Set(uint32(tx))
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nrf.UART0.PSEL.RXD.Set(uint32(rx))
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}
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func (i2c *I2C) setPins(scl, sda Pin) {
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i2c.Bus.PSEL.SCL.Set(uint32(scl))
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i2c.Bus.PSEL.SDA.Set(uint32(sda))
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}
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// PWM
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var (
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PWM0 = &PWM{PWM: nrf.PWM0}
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PWM1 = &PWM{PWM: nrf.PWM1}
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PWM2 = &PWM{PWM: nrf.PWM2}
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PWM3 = &PWM{PWM: nrf.PWM3}
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)
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// PDM represents a PDM device
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type PDM struct {
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device *nrf.PDM_Type
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defaultBuffer int16
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}
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// Configure is intended to set up the PDM interface prior to use.
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func (pdm *PDM) Configure(config PDMConfig) error {
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if config.DIN == 0 {
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return errors.New("No DIN pin provided in configuration")
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}
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if config.CLK == 0 {
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return errors.New("No CLK pin provided in configuration")
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}
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config.DIN.Configure(PinConfig{Mode: PinInput})
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config.CLK.Configure(PinConfig{Mode: PinOutput})
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pdm.device = nrf.PDM
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pdm.device.PSEL.DIN.Set(uint32(config.DIN))
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pdm.device.PSEL.CLK.Set(uint32(config.CLK))
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pdm.device.PDMCLKCTRL.Set(nrf.PDM_PDMCLKCTRL_FREQ_Default)
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pdm.device.RATIO.Set(nrf.PDM_RATIO_RATIO_Ratio64)
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pdm.device.GAINL.Set(nrf.PDM_GAINL_GAINL_DefaultGain)
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pdm.device.GAINR.Set(nrf.PDM_GAINR_GAINR_DefaultGain)
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pdm.device.ENABLE.Set(nrf.PDM_ENABLE_ENABLE_Enabled)
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if config.Stereo {
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pdm.device.MODE.Set(nrf.PDM_MODE_OPERATION_Stereo | nrf.PDM_MODE_EDGE_LeftRising)
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} else {
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pdm.device.MODE.Set(nrf.PDM_MODE_OPERATION_Mono | nrf.PDM_MODE_EDGE_LeftRising)
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}
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pdm.device.SAMPLE.SetPTR(uint32(uintptr(unsafe.Pointer(&pdm.defaultBuffer))))
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pdm.device.SAMPLE.SetMAXCNT_BUFFSIZE(1)
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pdm.device.SetTASKS_START(1)
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return nil
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}
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// Read stores a set of samples in the given target buffer.
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func (pdm *PDM) Read(buf []int16) (uint32, error) {
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pdm.device.SAMPLE.SetPTR(uint32(uintptr(unsafe.Pointer(&buf[0]))))
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pdm.device.SAMPLE.MAXCNT.Set(uint32(len(buf)))
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pdm.device.EVENTS_STARTED.Set(0)
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// Step 1: wait for new sampling to start for target buffer
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for !pdm.device.EVENTS_STARTED.HasBits(nrf.PDM_EVENTS_STARTED_EVENTS_STARTED) {
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}
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pdm.device.EVENTS_END.Set(0)
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// Step 2: swap out buffers for next recording so we don't continue to
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// write to the target buffer
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pdm.device.EVENTS_STARTED.Set(0)
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pdm.device.SAMPLE.SetPTR(uint32(uintptr(unsafe.Pointer(&pdm.defaultBuffer))))
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pdm.device.SAMPLE.MAXCNT.Set(1)
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// Step 3: wait for original event to end
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for pdm.device.EVENTS_END.HasBits(nrf.PDM_EVENTS_STOPPED_EVENTS_STOPPED) {
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}
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// Step 4: wait for default buffer to start recording before proceeding
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// otherwise we see the contents of target buffer change later
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for !pdm.device.EVENTS_STARTED.HasBits(nrf.PDM_EVENTS_STARTED_EVENTS_STARTED) {
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}
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return uint32(len(buf)), nil
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}
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const eraseBlockSizeValue = 4096
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func eraseBlockSize() int64 {
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return eraseBlockSizeValue
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}
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const spiMaxBufferSize = 0xffff // from the datasheet: TXD.MAXCNT and RXD.MAXCNT
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// ADC instance for the VDDH input pin. This pin is typically connected to USB
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// input voltage (~5V) or directly to a battery.
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var ADC_VDDH = ADC{adcVDDHPin}
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