machine/nrf52840: add support for ADC and PWM interfaces
Signed-off-by: Ron Evans <ron@hybridgroup.com>
Этот коммит содержится в:
Ron Evans
родитель
06ab3a836f
коммит
7857c7235b
2 изменённых файлов: 157 добавлений и 0 удалений
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@ -28,6 +28,16 @@ const (
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UART_RX_PIN = 8
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)
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// ADC pins
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const (
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ADC0 = 3
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ADC1 = 4
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ADC2 = 28
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ADC3 = 29
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ADC4 = 30
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ADC5 = 31
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)
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// I2C pins
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const (
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SDA_PIN = 26 // P0.26
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@ -4,6 +4,7 @@ package machine
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import (
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"device/nrf"
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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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@ -45,3 +46,149 @@ func (spi SPI) setPins(sck, mosi, miso uint8) {
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spi.Bus.PSEL.MOSI = nrf.RegValue(mosi)
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spi.Bus.PSEL.MISO = nrf.RegValue(miso)
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}
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// InitADC initializes the registers needed for ADC.
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func InitADC() {
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return // no specific setup on nrf52840 machine.
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}
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// Configure configures an ADC pin to be able to read analog data.
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func (a ADC) Configure() {
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return // no pin specific setup on nrf52840 machine.
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}
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// Get returns the current value of a ADC pin in the range 0..0xffff.
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func (a ADC) Get() uint16 {
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var pwmPin uint32
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var value int16
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switch a.Pin {
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case 2:
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pwmPin = nrf.SAADC_CH_PSELP_PSELP_AnalogInput0
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case 3:
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pwmPin = nrf.SAADC_CH_PSELP_PSELP_AnalogInput1
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case 4:
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pwmPin = nrf.SAADC_CH_PSELP_PSELP_AnalogInput2
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case 5:
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pwmPin = nrf.SAADC_CH_PSELP_PSELP_AnalogInput3
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case 28:
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pwmPin = nrf.SAADC_CH_PSELP_PSELP_AnalogInput4
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case 29:
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pwmPin = nrf.SAADC_CH_PSELP_PSELP_AnalogInput5
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case 30:
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pwmPin = nrf.SAADC_CH_PSELP_PSELP_AnalogInput6
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case 31:
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pwmPin = nrf.SAADC_CH_PSELP_PSELP_AnalogInput7
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default:
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return 0
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}
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nrf.SAADC.RESOLUTION = nrf.SAADC_RESOLUTION_VAL_12bit
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// Enable ADC.
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nrf.SAADC.ENABLE = (nrf.SAADC_ENABLE_ENABLE_Enabled << nrf.SAADC_ENABLE_ENABLE_Pos)
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for i := 0; i < 8; i++ {
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nrf.SAADC.CH[i].PSELN = nrf.SAADC_CH_PSELP_PSELP_NC
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nrf.SAADC.CH[i].PSELP = nrf.SAADC_CH_PSELP_PSELP_NC
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}
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// Configure ADC.
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nrf.SAADC.CH[0].CONFIG = ((nrf.SAADC_CH_CONFIG_RESP_Bypass << nrf.SAADC_CH_CONFIG_RESP_Pos) & nrf.SAADC_CH_CONFIG_RESP_Msk) |
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((nrf.SAADC_CH_CONFIG_RESP_Bypass << nrf.SAADC_CH_CONFIG_RESN_Pos) & nrf.SAADC_CH_CONFIG_RESN_Msk) |
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((nrf.SAADC_CH_CONFIG_GAIN_Gain1_5 << nrf.SAADC_CH_CONFIG_GAIN_Pos) & nrf.SAADC_CH_CONFIG_GAIN_Msk) |
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((nrf.SAADC_CH_CONFIG_REFSEL_Internal << nrf.SAADC_CH_CONFIG_REFSEL_Pos) & nrf.SAADC_CH_CONFIG_REFSEL_Msk) |
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((nrf.SAADC_CH_CONFIG_TACQ_3us << nrf.SAADC_CH_CONFIG_TACQ_Pos) & nrf.SAADC_CH_CONFIG_TACQ_Msk) |
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((nrf.SAADC_CH_CONFIG_MODE_SE << nrf.SAADC_CH_CONFIG_MODE_Pos) & nrf.SAADC_CH_CONFIG_MODE_Msk)
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// Set pin to read.
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nrf.SAADC.CH[0].PSELN = nrf.RegValue(pwmPin)
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nrf.SAADC.CH[0].PSELP = nrf.RegValue(pwmPin)
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// Destination for sample result.
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nrf.SAADC.RESULT.PTR = nrf.RegValue(uintptr(unsafe.Pointer(&value)))
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nrf.SAADC.RESULT.MAXCNT = 1 // One sample
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// Start tasks.
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nrf.SAADC.TASKS_START = 1
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for nrf.SAADC.EVENTS_STARTED == 0 {
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}
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nrf.SAADC.EVENTS_STARTED = 0x00
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// Start the sample task.
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nrf.SAADC.TASKS_SAMPLE = 1
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// Wait until the sample task is done.
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for nrf.SAADC.EVENTS_END == 0 {
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}
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nrf.SAADC.EVENTS_END = 0x00
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// Stop the ADC
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nrf.SAADC.TASKS_STOP = 1
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for nrf.SAADC.EVENTS_STOPPED == 0 {
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}
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nrf.SAADC.EVENTS_STOPPED = 0
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// Disable the ADC.
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nrf.SAADC.ENABLE = (nrf.SAADC_ENABLE_ENABLE_Disabled << nrf.SAADC_ENABLE_ENABLE_Pos)
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if value < 0 {
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value = 0
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}
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// Return 16-bit result from 12-bit value.
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return uint16(value << 4)
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}
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// PWM
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var (
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pwmChannelPins = [4]uint32{0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF}
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pwms = [4]*nrf.PWM_Type{nrf.PWM0, nrf.PWM1, nrf.PWM2, nrf.PWM3}
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pwmChannelSequence [4]uint16
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)
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// InitPWM initializes the registers needed for PWM.
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func InitPWM() {
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return
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}
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// Configure configures a PWM pin for output.
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func (pwm PWM) Configure() {
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}
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// Set turns on the duty cycle for a PWM pin using the provided value.
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func (pwm PWM) Set(value uint16) {
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for i := 0; i < 4; i++ {
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if pwmChannelPins[i] == 0xFFFFFFFF || pwmChannelPins[i] == uint32(pwm.Pin) {
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pwmChannelPins[i] = uint32(pwm.Pin)
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pwmChannelSequence[i] = (value >> 2) | 0x8000 // set bit 15 to invert polarity
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p := pwms[i]
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p.PSEL.OUT[0] = nrf.RegValue(pwm.Pin)
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p.PSEL.OUT[1] = nrf.RegValue(pwm.Pin)
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p.PSEL.OUT[2] = nrf.RegValue(pwm.Pin)
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p.PSEL.OUT[3] = nrf.RegValue(pwm.Pin)
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p.ENABLE = (nrf.PWM_ENABLE_ENABLE_Enabled << nrf.PWM_ENABLE_ENABLE_Pos)
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p.PRESCALER = nrf.PWM_PRESCALER_PRESCALER_DIV_2
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p.MODE = nrf.PWM_MODE_UPDOWN_Up
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p.COUNTERTOP = 16384 // frequency
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p.LOOP = 0
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p.DECODER = (nrf.PWM_DECODER_LOAD_Common << nrf.PWM_DECODER_LOAD_Pos) | (nrf.PWM_DECODER_MODE_RefreshCount << nrf.PWM_DECODER_MODE_Pos)
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p.SEQ[0].PTR = nrf.RegValue(uintptr(unsafe.Pointer(&pwmChannelSequence[i])))
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p.SEQ[0].CNT = 1
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p.SEQ[0].REFRESH = 1
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p.SEQ[0].ENDDELAY = 0
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p.TASKS_SEQSTART[0] = 1
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break
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}
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}
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}
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