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machine/esp32: add PWM support using the LEDC peripheral for classic esp32 board #5669

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2 changes: 2 additions & 0 deletions make/smoketest.mk
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Expand Up @@ -477,6 +477,8 @@ ifneq ($(XTENSA), 0)
@$(MD5SUM) $(SMOKE_OUT).bin
$(TINYGO) build -size short -o $(SMOKE_OUT).bin -target=esp32-coreboard-v2 examples/adc
@$(MD5SUM) $(SMOKE_OUT).bin
$(TINYGO) build -size short -o $(SMOKE_OUT).bin -target=esp32-coreboard-v2 examples/pwm
@$(MD5SUM) $(SMOKE_OUT).bin
$(TINYGO) build -size short -o $(SMOKE_OUT).bin -target=esp32c3-generic examples/machinetest
@$(MD5SUM) $(SMOKE_OUT).bin
$(TINYGO) build -size short -o $(SMOKE_OUT).bin -target=esp32s3-generic examples/machinetest
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11 changes: 11 additions & 0 deletions src/examples/pwm/esp32-coreboard-v2.go
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//go:build esp32_coreboard_v2

package main

import "machine"

var (
pwm = machine.PWM0
pinA = machine.GPIO18
pinB = machine.GPIO19
)
300 changes: 300 additions & 0 deletions src/machine/machine_esp32_pwm.go
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//go:build esp32

// PWM on the classic ESP32 uses the LEDC peripheral.
//
// LEDC here has two halves: a high-speed one and a low-speed one. This file uses
// the high-speed half. It gives 4 timers (PWM0-PWM3) and 8 channels.
//
// The code that is the same on every ESP32 chip is in machine_esp32xx_pwm.go.
// This file adds only the parts that are different here.
//
// Three things are different from the ESP32-C3 and the ESP32-S3:
//
// - The clock is switched on in DPORT. The newer chips renamed that block to
// SYSTEM. This chip also has no LEDC.CONF_CLK_EN bit.
// - Register names start with HS, for example HSTIMER0_CONF and HSCH0_CONF0.
// - There is no PARA_UP bit. On the C3 and S3 you set PARA_UP to say "apply my
// changes now". Here the channel applies them by itself, at the end of the
// period it is in. That is what makes it "high speed".
// See the ESP32 TRM, chapter "LED PWM Controller".

package machine

import "device/esp"

// The GPIO matrix can send an internal signal to almost any pin. Each signal has
// a number. High-speed LEDC channel 0 is number 71, and the rest follow on from
// there, so channels 0 to 7 are 71 to 78.
// (From Espressif's soc/gpio_sig_map.h: LEDC_HS_SIG_OUT0_IDX.)
const LEDC_HS_SIG_OUT0_IDX = 71

const ledcChannelsESP32 = 8

var (
PWM0 = &LEDCPWM{SigOutBase: LEDC_HS_SIG_OUT0_IDX, NumChannels: ledcChannelsESP32, timerNum: 0}
PWM1 = &LEDCPWM{SigOutBase: LEDC_HS_SIG_OUT0_IDX, NumChannels: ledcChannelsESP32, timerNum: 1}
PWM2 = &LEDCPWM{SigOutBase: LEDC_HS_SIG_OUT0_IDX, NumChannels: ledcChannelsESP32, timerNum: 2}
PWM3 = &LEDCPWM{SigOutBase: LEDC_HS_SIG_OUT0_IDX, NumChannels: ledcChannelsESP32, timerNum: 3}
)

// enableClock turns the LEDC hardware on and picks its clock.
func (pwm *LEDCPWM) enableClock() {
// Every peripheral starts switched off, to save power. Turn the LEDC clock
// on, then take it out of reset. These registers are in DPORT on this chip.
// The C3 and S3 call the same block SYSTEM.
esp.DPORT.SetPERIP_RST_EN_LEDC_RST(1)
esp.DPORT.SetPERIP_CLK_EN_LEDC_CLK_EN(1)
esp.DPORT.SetPERIP_RST_EN_LEDC_RST(0)

// Use APB_CLK, which runs at 80MHz. This chip has no CONF_CLK_EN bit, so
// there is nothing more to switch on.
esp.LEDC.SetCONF_APB_CLK_SEL(1)
}

// setTimerConf writes the resolution and the divider that Configure worked out
// into one timer.
//
// Watch TICK_SEL. It is 1 here, not 0. On this chip:
//
// 1 = APB_CLK, 80MHz <- what we want
// 0 = REF_TICK, 1MHz
//
// The low-speed timers on the C3 and S3 use the opposite meaning, so their code
// writes 0. Writing 0 here would make every frequency 80 times too slow.
//
// These timers have no PARA_UP bit. The short reset pulse at the end is what
// makes the new values take effect.
func (pwm *LEDCPWM) setTimerConf(dutyRes uint8, divReg uint32) {
switch pwm.timerNum {
case 0:
esp.LEDC.SetHSTIMER0_CONF_DUTY_RES(uint32(dutyRes))
esp.LEDC.SetHSTIMER0_CONF_DIV_NUM(divReg)
esp.LEDC.SetHSTIMER0_CONF_TICK_SEL(1)
esp.LEDC.SetHSTIMER0_CONF_PAUSE(0)
esp.LEDC.SetHSTIMER0_CONF_RST(1)
esp.LEDC.SetHSTIMER0_CONF_RST(0)
case 1:
esp.LEDC.SetHSTIMER1_CONF_DUTY_RES(uint32(dutyRes))
esp.LEDC.SetHSTIMER1_CONF_DIV_NUM(divReg)
esp.LEDC.SetHSTIMER1_CONF_TICK_SEL(1)
esp.LEDC.SetHSTIMER1_CONF_PAUSE(0)
esp.LEDC.SetHSTIMER1_CONF_RST(1)
esp.LEDC.SetHSTIMER1_CONF_RST(0)
case 2:
esp.LEDC.SetHSTIMER2_CONF_DUTY_RES(uint32(dutyRes))
esp.LEDC.SetHSTIMER2_CONF_DIV_NUM(divReg)
esp.LEDC.SetHSTIMER2_CONF_TICK_SEL(1)
esp.LEDC.SetHSTIMER2_CONF_PAUSE(0)
esp.LEDC.SetHSTIMER2_CONF_RST(1)
esp.LEDC.SetHSTIMER2_CONF_RST(0)
case 3:
esp.LEDC.SetHSTIMER3_CONF_DUTY_RES(uint32(dutyRes))
esp.LEDC.SetHSTIMER3_CONF_DIV_NUM(divReg)
esp.LEDC.SetHSTIMER3_CONF_TICK_SEL(1)
esp.LEDC.SetHSTIMER3_CONF_PAUSE(0)
esp.LEDC.SetHSTIMER3_CONF_RST(1)
esp.LEDC.SetHSTIMER3_CONF_RST(0)
}
}

// chanOp does the work for one channel, numbered 0 to 7. It either sets the
// channel up, changes its duty, or flips its idle level.
//
// Each channel has its own registers, and each register has its own generated
// setter function. There is no array to index, so this has to be a long switch.
// The C3 and S3 files have the same shape.
//
// DUTY_SCALE is set to 0. LEDC can fade slowly from one duty to the next; 0
// turns that off, so the duty changes in a single step.
func (pwm *LEDCPWM) chanOp(ch uint8, op ledcChanOp, duty uint32, inverting bool) {
invVal := uint32(0)
if inverting {
invVal = 1
}
switch ch {
case 0:
switch op {
case ledcChanOpInit:
esp.LEDC.SetHSCH0_CONF0_TIMER_SEL(uint32(pwm.timerNum))
esp.LEDC.SetHSCH0_CONF0_SIG_OUT_EN(1)
esp.LEDC.SetHSCH0_CONF0_IDLE_LV(0)
esp.LEDC.SetHSCH0_HPOINT_HPOINT(0)
esp.LEDC.SetHSCH0_DUTY_DUTY(0)
esp.LEDC.SetHSCH0_CONF1_DUTY_SCALE(0)
esp.LEDC.SetHSCH0_CONF1_DUTY_CYCLE(1)
esp.LEDC.SetHSCH0_CONF1_DUTY_NUM(1)
esp.LEDC.SetHSCH0_CONF1_DUTY_INC(1)
esp.LEDC.SetHSCH0_CONF1_DUTY_START(1)
case ledcChanOpSetDuty:
esp.LEDC.SetHSCH0_DUTY_DUTY(duty)
esp.LEDC.SetHSCH0_CONF1_DUTY_CYCLE(1)
esp.LEDC.SetHSCH0_CONF1_DUTY_NUM(1)
esp.LEDC.SetHSCH0_CONF1_DUTY_INC(1)
esp.LEDC.SetHSCH0_CONF1_DUTY_START(1)
esp.LEDC.SetHSCH0_CONF0_SIG_OUT_EN(1)
case ledcChanOpSetInvert:
esp.LEDC.SetHSCH0_CONF0_IDLE_LV(invVal)
}
case 1:
switch op {
case ledcChanOpInit:
esp.LEDC.SetHSCH1_CONF0_TIMER_SEL(uint32(pwm.timerNum))
esp.LEDC.SetHSCH1_CONF0_SIG_OUT_EN(1)
esp.LEDC.SetHSCH1_CONF0_IDLE_LV(0)
esp.LEDC.SetHSCH1_HPOINT_HPOINT(0)
esp.LEDC.SetHSCH1_DUTY_DUTY(0)
esp.LEDC.SetHSCH1_CONF1_DUTY_SCALE(0)
esp.LEDC.SetHSCH1_CONF1_DUTY_CYCLE(1)
esp.LEDC.SetHSCH1_CONF1_DUTY_NUM(1)
esp.LEDC.SetHSCH1_CONF1_DUTY_INC(1)
esp.LEDC.SetHSCH1_CONF1_DUTY_START(1)
case ledcChanOpSetDuty:
esp.LEDC.SetHSCH1_DUTY_DUTY(duty)
esp.LEDC.SetHSCH1_CONF1_DUTY_CYCLE(1)
esp.LEDC.SetHSCH1_CONF1_DUTY_NUM(1)
esp.LEDC.SetHSCH1_CONF1_DUTY_INC(1)
esp.LEDC.SetHSCH1_CONF1_DUTY_START(1)
esp.LEDC.SetHSCH1_CONF0_SIG_OUT_EN(1)
case ledcChanOpSetInvert:
esp.LEDC.SetHSCH1_CONF0_IDLE_LV(invVal)
}
case 2:
switch op {
case ledcChanOpInit:
esp.LEDC.SetHSCH2_CONF0_TIMER_SEL(uint32(pwm.timerNum))
esp.LEDC.SetHSCH2_CONF0_SIG_OUT_EN(1)
esp.LEDC.SetHSCH2_CONF0_IDLE_LV(0)
esp.LEDC.SetHSCH2_HPOINT_HPOINT(0)
esp.LEDC.SetHSCH2_DUTY_DUTY(0)
esp.LEDC.SetHSCH2_CONF1_DUTY_SCALE(0)
esp.LEDC.SetHSCH2_CONF1_DUTY_CYCLE(1)
esp.LEDC.SetHSCH2_CONF1_DUTY_NUM(1)
esp.LEDC.SetHSCH2_CONF1_DUTY_INC(1)
esp.LEDC.SetHSCH2_CONF1_DUTY_START(1)
case ledcChanOpSetDuty:
esp.LEDC.SetHSCH2_DUTY_DUTY(duty)
esp.LEDC.SetHSCH2_CONF1_DUTY_CYCLE(1)
esp.LEDC.SetHSCH2_CONF1_DUTY_NUM(1)
esp.LEDC.SetHSCH2_CONF1_DUTY_INC(1)
esp.LEDC.SetHSCH2_CONF1_DUTY_START(1)
esp.LEDC.SetHSCH2_CONF0_SIG_OUT_EN(1)
case ledcChanOpSetInvert:
esp.LEDC.SetHSCH2_CONF0_IDLE_LV(invVal)
}
case 3:
switch op {
case ledcChanOpInit:
esp.LEDC.SetHSCH3_CONF0_TIMER_SEL(uint32(pwm.timerNum))
esp.LEDC.SetHSCH3_CONF0_SIG_OUT_EN(1)
esp.LEDC.SetHSCH3_CONF0_IDLE_LV(0)
esp.LEDC.SetHSCH3_HPOINT_HPOINT(0)
esp.LEDC.SetHSCH3_DUTY_DUTY(0)
esp.LEDC.SetHSCH3_CONF1_DUTY_SCALE(0)
esp.LEDC.SetHSCH3_CONF1_DUTY_CYCLE(1)
esp.LEDC.SetHSCH3_CONF1_DUTY_NUM(1)
esp.LEDC.SetHSCH3_CONF1_DUTY_INC(1)
esp.LEDC.SetHSCH3_CONF1_DUTY_START(1)
case ledcChanOpSetDuty:
esp.LEDC.SetHSCH3_DUTY_DUTY(duty)
esp.LEDC.SetHSCH3_CONF1_DUTY_CYCLE(1)
esp.LEDC.SetHSCH3_CONF1_DUTY_NUM(1)
esp.LEDC.SetHSCH3_CONF1_DUTY_INC(1)
esp.LEDC.SetHSCH3_CONF1_DUTY_START(1)
esp.LEDC.SetHSCH3_CONF0_SIG_OUT_EN(1)
case ledcChanOpSetInvert:
esp.LEDC.SetHSCH3_CONF0_IDLE_LV(invVal)
}
case 4:
switch op {
case ledcChanOpInit:
esp.LEDC.SetHSCH4_CONF0_TIMER_SEL(uint32(pwm.timerNum))
esp.LEDC.SetHSCH4_CONF0_SIG_OUT_EN(1)
esp.LEDC.SetHSCH4_CONF0_IDLE_LV(0)
esp.LEDC.SetHSCH4_HPOINT_HPOINT(0)
esp.LEDC.SetHSCH4_DUTY_DUTY(0)
esp.LEDC.SetHSCH4_CONF1_DUTY_SCALE(0)
esp.LEDC.SetHSCH4_CONF1_DUTY_CYCLE(1)
esp.LEDC.SetHSCH4_CONF1_DUTY_NUM(1)
esp.LEDC.SetHSCH4_CONF1_DUTY_INC(1)
esp.LEDC.SetHSCH4_CONF1_DUTY_START(1)
case ledcChanOpSetDuty:
esp.LEDC.SetHSCH4_DUTY_DUTY(duty)
esp.LEDC.SetHSCH4_CONF1_DUTY_CYCLE(1)
esp.LEDC.SetHSCH4_CONF1_DUTY_NUM(1)
esp.LEDC.SetHSCH4_CONF1_DUTY_INC(1)
esp.LEDC.SetHSCH4_CONF1_DUTY_START(1)
esp.LEDC.SetHSCH4_CONF0_SIG_OUT_EN(1)
case ledcChanOpSetInvert:
esp.LEDC.SetHSCH4_CONF0_IDLE_LV(invVal)
}
case 5:
switch op {
case ledcChanOpInit:
esp.LEDC.SetHSCH5_CONF0_TIMER_SEL(uint32(pwm.timerNum))
esp.LEDC.SetHSCH5_CONF0_SIG_OUT_EN(1)
esp.LEDC.SetHSCH5_CONF0_IDLE_LV(0)
esp.LEDC.SetHSCH5_HPOINT_HPOINT(0)
esp.LEDC.SetHSCH5_DUTY_DUTY(0)
esp.LEDC.SetHSCH5_CONF1_DUTY_SCALE(0)
esp.LEDC.SetHSCH5_CONF1_DUTY_CYCLE(1)
esp.LEDC.SetHSCH5_CONF1_DUTY_NUM(1)
esp.LEDC.SetHSCH5_CONF1_DUTY_INC(1)
esp.LEDC.SetHSCH5_CONF1_DUTY_START(1)
case ledcChanOpSetDuty:
esp.LEDC.SetHSCH5_DUTY_DUTY(duty)
esp.LEDC.SetHSCH5_CONF1_DUTY_CYCLE(1)
esp.LEDC.SetHSCH5_CONF1_DUTY_NUM(1)
esp.LEDC.SetHSCH5_CONF1_DUTY_INC(1)
esp.LEDC.SetHSCH5_CONF1_DUTY_START(1)
esp.LEDC.SetHSCH5_CONF0_SIG_OUT_EN(1)
case ledcChanOpSetInvert:
esp.LEDC.SetHSCH5_CONF0_IDLE_LV(invVal)
}
case 6:
switch op {
case ledcChanOpInit:
esp.LEDC.SetHSCH6_CONF0_TIMER_SEL(uint32(pwm.timerNum))
esp.LEDC.SetHSCH6_CONF0_SIG_OUT_EN(1)
esp.LEDC.SetHSCH6_CONF0_IDLE_LV(0)
esp.LEDC.SetHSCH6_HPOINT_HPOINT(0)
esp.LEDC.SetHSCH6_DUTY_DUTY(0)
esp.LEDC.SetHSCH6_CONF1_DUTY_SCALE(0)
esp.LEDC.SetHSCH6_CONF1_DUTY_CYCLE(1)
esp.LEDC.SetHSCH6_CONF1_DUTY_NUM(1)
esp.LEDC.SetHSCH6_CONF1_DUTY_INC(1)
esp.LEDC.SetHSCH6_CONF1_DUTY_START(1)
case ledcChanOpSetDuty:
esp.LEDC.SetHSCH6_DUTY_DUTY(duty)
esp.LEDC.SetHSCH6_CONF1_DUTY_CYCLE(1)
esp.LEDC.SetHSCH6_CONF1_DUTY_NUM(1)
esp.LEDC.SetHSCH6_CONF1_DUTY_INC(1)
esp.LEDC.SetHSCH6_CONF1_DUTY_START(1)
esp.LEDC.SetHSCH6_CONF0_SIG_OUT_EN(1)
case ledcChanOpSetInvert:
esp.LEDC.SetHSCH6_CONF0_IDLE_LV(invVal)
}
case 7:
switch op {
case ledcChanOpInit:
esp.LEDC.SetHSCH7_CONF0_TIMER_SEL(uint32(pwm.timerNum))
esp.LEDC.SetHSCH7_CONF0_SIG_OUT_EN(1)
esp.LEDC.SetHSCH7_CONF0_IDLE_LV(0)
esp.LEDC.SetHSCH7_HPOINT_HPOINT(0)
esp.LEDC.SetHSCH7_DUTY_DUTY(0)
esp.LEDC.SetHSCH7_CONF1_DUTY_SCALE(0)
esp.LEDC.SetHSCH7_CONF1_DUTY_CYCLE(1)
esp.LEDC.SetHSCH7_CONF1_DUTY_NUM(1)
esp.LEDC.SetHSCH7_CONF1_DUTY_INC(1)
esp.LEDC.SetHSCH7_CONF1_DUTY_START(1)
case ledcChanOpSetDuty:
esp.LEDC.SetHSCH7_DUTY_DUTY(duty)
esp.LEDC.SetHSCH7_CONF1_DUTY_CYCLE(1)
esp.LEDC.SetHSCH7_CONF1_DUTY_NUM(1)
esp.LEDC.SetHSCH7_CONF1_DUTY_INC(1)
esp.LEDC.SetHSCH7_CONF1_DUTY_START(1)
esp.LEDC.SetHSCH7_CONF0_SIG_OUT_EN(1)
case ledcChanOpSetInvert:
esp.LEDC.SetHSCH7_CONF0_IDLE_LV(invVal)
}
}
}
69 changes: 69 additions & 0 deletions src/machine/machine_esp32xx_ls_pwm.go
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//go:build esp32c3 || esp32s3

// Low-speed LEDC code, shared by the ESP32-C3 and the ESP32-S3.
//
// Both chips have only the low-speed LEDC block. Their clock and timer registers
// use the same names, so one copy of this code serves both.
//
// The classic ESP32 has a high-speed block instead, with different register
// names. Its versions of these two functions are in machine_esp32_pwm.go.
//
// The SVD (lib/cmsis-svd/data/Espressif/esp32s3.svd) describes the two bits that
// make a change take effect on these chips. CONF0.PARA_UP "updates HPOINT,
// DUTY_START, SIG_OUT_EN, TIMER_SEL, DUTY_NUM, DUTY_CYCLE, DUTY_SCALE, DUTY_INC
// for channel and is auto-cleared by hardware". CONF1.DUTY_START "other CONF1
// fields take effect when this bit is set to 1".

package machine

import "device/esp"

// enableClock turns the LEDC hardware on and picks APB_CLK as its clock.
func (pwm *LEDCPWM) enableClock() {
// Enable LEDC clock and release reset (SYSTEM perip_clk_en0 / perip_rst_en0).
esp.SYSTEM.SetPERIP_RST_EN0_LEDC_RST(1)
esp.SYSTEM.SetPERIP_CLK_EN0_LEDC_CLK_EN(1)
esp.SYSTEM.SetPERIP_RST_EN0_LEDC_RST(0)

// LEDC global: APB clock source, enable internal clock.
esp.LEDC.SetCONF_APB_CLK_SEL(1)
esp.LEDC.SetCONF_CLK_EN(1)
}

func (pwm *LEDCPWM) setTimerConf(dutyRes uint8, divReg uint32) {
t := pwm.timerNum
switch t {
case 0:
esp.LEDC.SetTIMER0_CONF_DUTY_RES(uint32(dutyRes))
esp.LEDC.SetTIMER0_CONF_CLK_DIV(divReg)
esp.LEDC.SetTIMER0_CONF_TICK_SEL(0)
esp.LEDC.SetTIMER0_CONF_PAUSE(0)
esp.LEDC.SetTIMER0_CONF_RST(1)
esp.LEDC.SetTIMER0_CONF_RST(0)
esp.LEDC.SetTIMER0_CONF_PARA_UP(1)
case 1:
esp.LEDC.SetTIMER1_CONF_DUTY_RES(uint32(dutyRes))
esp.LEDC.SetTIMER1_CONF_CLK_DIV(divReg)
esp.LEDC.SetTIMER1_CONF_TICK_SEL(0)
esp.LEDC.SetTIMER1_CONF_PAUSE(0)
esp.LEDC.SetTIMER1_CONF_RST(1)
esp.LEDC.SetTIMER1_CONF_RST(0)
esp.LEDC.SetTIMER1_CONF_PARA_UP(1)
case 2:
esp.LEDC.SetTIMER2_CONF_DUTY_RES(uint32(dutyRes))
esp.LEDC.SetTIMER2_CONF_CLK_DIV(divReg)
esp.LEDC.SetTIMER2_CONF_TICK_SEL(0)
esp.LEDC.SetTIMER2_CONF_PAUSE(0)
esp.LEDC.SetTIMER2_CONF_RST(1)
esp.LEDC.SetTIMER2_CONF_RST(0)
esp.LEDC.SetTIMER2_CONF_PARA_UP(1)
case 3:
esp.LEDC.SetTIMER3_CONF_DUTY_RES(uint32(dutyRes))
esp.LEDC.SetTIMER3_CONF_CLK_DIV(divReg)
esp.LEDC.SetTIMER3_CONF_TICK_SEL(0)
esp.LEDC.SetTIMER3_CONF_PAUSE(0)
esp.LEDC.SetTIMER3_CONF_RST(1)
esp.LEDC.SetTIMER3_CONF_RST(0)
esp.LEDC.SetTIMER3_CONF_PARA_UP(1)
}
}
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