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BREAKING - analogWriteRange 8-bit default (#7456)

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Matching standard Arduino cores, make the default analogWrite() take
values from 0...255.  Users can always use the analogWriteRange() call
to change to a different setup.

Add a `analogWriteResolution` which takes a number of bits and sets
the range from 0...(1<<bits)-1, part of the standard Arduino API.

Remove the PWMRANGE define.  It's non-standard and not generally valid
(i.e. it's fixed at 1024 of 256, but the real range varies depending on
what you last set).

Also add note about the change and how to fix pre 3.0 applications.

Fixes #2895
This commit is contained in:
Earle F. Philhower, III
2020-07-28 17:39:38 -07:00
committed by GitHub
parent 33083861c8
commit a679869155
3 changed files with 28 additions and 8 deletions
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3
cores/esp8266/Arduino.h
View File

@ -43,8 +43,6 @@ extern "C" {
#define HIGH 0x1
#define LOW 0x0
#define PWMRANGE 1023
//GPIO FUNCTIONS
#define INPUT 0x00
#define INPUT_PULLUP 0x02
@ -176,6 +174,7 @@ int analogRead(uint8_t pin);
void analogReference(uint8_t mode);
void analogWrite(uint8_t pin, int val);
void analogWriteFreq(uint32_t freq);
void analogWriteResolution(int res);
void analogWriteRange(uint32_t range);
unsigned long millis(void);

15
cores/esp8266/core_esp8266_wiring_pwm.cpp
View File

@ -27,15 +27,21 @@
extern "C" {
static uint32_t analogMap = 0;
static int32_t analogScale = PWMRANGE;
static int32_t analogScale = 255; // Match upstream default, breaking change from 2.x.x
static uint16_t analogFreq = 1000;
extern void __analogWriteRange(uint32_t range) {
if (range > 0) {
if ((range >= 15) && (range <= 65535)) {
analogScale = range;
}
}
extern void __analogWriteResolution(int res) {
if ((res >= 4) && (res <= 16)) {
analogScale = (1 << res) - 1;
}
}
extern void __analogWriteFreq(uint32_t freq) {
if (freq < 100) {
analogFreq = 100;
@ -57,6 +63,10 @@ extern void __analogWrite(uint8_t pin, int val) {
val = analogScale;
}
// Per the Arduino docs at https://www.arduino.cc/reference/en/language/functions/analog-io/analogwrite/
// val: the duty cycle: between 0 (always off) and 255 (always on).
// So if val = 0 we have digitalWrite(LOW), if we have val==range we have digitalWrite(HIGH)
analogMap &= ~(1 << pin);
uint32_t high = (analogPeriod * val) / analogScale;
uint32_t low = analogPeriod - high;
@ -75,5 +85,6 @@ extern void __analogWrite(uint8_t pin, int val) {
extern void analogWrite(uint8_t pin, int val) __attribute__((weak, alias("__analogWrite")));
extern void analogWriteFreq(uint32_t freq) __attribute__((weak, alias("__analogWriteFreq")));
extern void analogWriteRange(uint32_t range) __attribute__((weak, alias("__analogWriteRange")));
extern void analogWriteResolution(int res) __attribute__((weak, alias("__analogWriteResolution")));
};