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working code for sigma delta generator #4119

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d746752
working code for sigma delta generator
stefaandesmet2003 Jan 8, 2018
a11cb99
Merge branch 'master' into master
stefaandesmet2003 Jan 10, 2018
85b9323
removed example code from header file
stefaandesmet2003 Jan 10, 2018
648483c
example for the esp8266 sigma delta generator hardware
stefaandesmet2003 Jan 10, 2018
46cf8c4
Merge branch 'master' into master
stefaandesmet2003 Jan 23, 2018
c5351a0
modified interface in line with ESP32 implementation
stefaandesmet2003 Jan 23, 2018
a1f8886
modified interface in line with ESP32 implementation
stefaandesmet2003 Jan 23, 2018
385b7a2
changes requested by earlphilhower
stefaandesmet2003 Mar 9, 2018
a60f949
update for travis style_check
stefaandesmet2003 Mar 9, 2018
6d177fd
Merge branch 'master' into master
stefaandesmet2003 Mar 9, 2018
717bdc3
remove unused parameter in sigmaDeltaGetPrescaler()
stefaandesmet2003 Mar 9, 2018
4c7ad74
travis doesn't like compiler warnings
stefaandesmet2003 Mar 9, 2018
0a1189e
correct comment for travis
stefaandesmet2003 Mar 9, 2018
83aeecd
changed BUILTIN_LED to LED_BUILTIN
stefaandesmet2003 Mar 9, 2018
4ebb183
remove unused test code
stefaandesmet2003 Mar 9, 2018
ab7204c
for travis style_check
stefaandesmet2003 Mar 10, 2018
d67fa53
another attempt for travis style_check
stefaandesmet2003 Mar 10, 2018
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114 changes: 56 additions & 58 deletions cores/esp8266/core_esp8266_sigma_delta.c
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Original file line number Diff line number Diff line change
@@ -1,32 +1,3 @@
/*
/******************************************************************************
* Sigma delta module

This module controls the esp8266 internal sigma delta source
Each pin can be connected to the sigma delta source
The target duty and frequency can be modified via the register GPIO_SIGMA_DELTA

THE TARGET FREQUENCY IS DEFINED AS:

FREQ = 80,000,000/prescaler * target /256 HZ, 0<target<128
FREQ = 80,000,000/prescaler * (256-target) /256 HZ, 128<target<256
target: duty ,0-255
prescaler: clk_div,0-255
so the target and prescale will both affect the freq.

Usage :
1. sigma_delta_enable() : activate the sigma delta source with default prescalar (0) & target (0)
2. sigma_delta_attachPin(pin), any pin 0..15, TBC if gpio16 supports sigma-delta source
This will set the pin to NORMAL output mode (pinMode(pin,OUTPUT))
3. sigma_delta_setPrescaler(uint8_t) : reduce the output frequencies
4. sigma_delta_setTarget(uint8_t) : set the output signal duty cycle, duty cycle = target/256

5. sigma_delta_detachPin(pin), this will revert the pin to NORMAL output mode & GPIO source.
The sigma delta source remains on until :
6. sigma_delta_disable()

*******************************************************************************/

#include "Arduino.h" // using pinMode
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Needs standard licence header, please.

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ok done


// definitions in esp8266_peri.h style
Expand All @@ -36,35 +7,36 @@ The sigma delta source remains on until :
#define GPSDE 16 // enable

/******************************************************************************
* FunctionName : sigma_delta_start
* FunctionName : sigmaDeltaEnable
* Description : enable the internal sigma delta source
* Parameters : none
* Returns : none
*******************************************************************************/
void ICACHE_FLASH_ATTR sigma_delta_enable()
void ICACHE_FLASH_ATTR sigmaDeltaEnable()
{
GPSD = (0 << GPSDT) | (0 << GPSDP) | (1 << GPSDE); //SIGMA_DELTA_TARGET(0) | SIGMA_DELTA_PRESCALER(0) | SIGMA_DELTA_ENABLE(ENABLED)
}

/******************************************************************************
* FunctionName : sigma_delta_disable
* FunctionName : sigmaDeltaDisable
* Description : stop the internal sigma delta source
* Parameters : none
* Returns : none
*******************************************************************************/
void ICACHE_FLASH_ATTR sigma_delta_disable()
void ICACHE_FLASH_ATTR sigmaDeltaDisable()
{
GPSD = (0 << GPSDT) | (0 << GPSDP) | (0 << GPSDE); //SIGMA_DELTA_TARGET(0) | SIGMA_DELTA_PRESCALER(0) | SIGMA_DELTA_ENABLE(DISABLED)
}

/******************************************************************************
* FunctionName : sigma_delta_attachPin
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Some FunctionName comments got updated to camelCase, but some like this did not.

* Description : connects the sigma delta source to a physical output pin
* Parameters : pin (0..15)
* Parameters : pin (0..15), channel = unused, for compatibility with ESP32
* Returns : none
*******************************************************************************/
void ICACHE_FLASH_ATTR sigma_delta_attachPin(uint8_t pin)
void ICACHE_FLASH_ATTR sigmaDeltaAttachPin(uint8_t pin, uint8_t channel)
{
(void) channel;
// make the chosen pin an output pin
pinMode (pin, OUTPUT);
if (pin < 16) {
Expand All @@ -79,7 +51,7 @@ void ICACHE_FLASH_ATTR sigma_delta_attachPin(uint8_t pin)
* Parameters : pin (0..16)
* Returns : none
*******************************************************************************/
void ICACHE_FLASH_ATTR sigma_delta_detachPin(uint8_t pin)
void ICACHE_FLASH_ATTR sigmaDeltaDetachPin(uint8_t pin)
{
if (pin < 16) {
// set its source to the sigma delta source
Expand All @@ -88,12 +60,12 @@ void ICACHE_FLASH_ATTR sigma_delta_detachPin(uint8_t pin)
}

/******************************************************************************
* FunctionName : sigma_delta_isPinAttached
* FunctionName : sigmaDeltaIsPinAttached
* Description : query if pin is attached
* Parameters : pin (0..16)
* Returns : bool
*******************************************************************************/
bool ICACHE_FLASH_ATTR sigma_delta_isPinAttached(uint8_t pin)
bool ICACHE_FLASH_ATTR sigmaDeltaIsPinAttached(uint8_t pin)
{
if (pin < 16) {
// set its source to the sigma delta source
Expand All @@ -104,51 +76,77 @@ bool ICACHE_FLASH_ATTR sigma_delta_isPinAttached(uint8_t pin)
}

/******************************************************************************
* FunctionName : sigma_delta_getTarget
* Description : get the target value from the GPIO_SIGMA_DELTA register
* Parameters : none
* Returns : uint8_t target value 0..255
* FunctionName : sigmaDeltaSetup
* Description : start the sigma delta generator with the chosen parameters
* Parameters : channel = unused (for compatibility with ESP32),
* freq : 1220-312500 (lowest frequency in the output signal's spectrum)
* Returns : uint32_t the actual frequency, closest to the input parameter
*******************************************************************************/
uint8_t ICACHE_FLASH_ATTR sigma_delta_getTarget(void)
uint32_t ICACHE_FLASH_ATTR sigmaDeltaSetup(uint8_t channel, uint32_t freq)
{
return (uint8_t)((GPSD >> GPSDT) & 0xFF);
(void) channel;

uint32_t prescaler = ((uint32_t)10000000/(freq*32)) - 1;

if(prescaler > 0xFF) {
prescaler = 0xFF;
}
sigmaDeltaEnable();
sigmaDeltaSetPrescaler ((uint8_t) prescaler);
//sigmaDeltaSetTarget ((uint8_t) 0x80); // 50% duty cycle

return 10000000/((prescaler + 1) * 32);
}

/******************************************************************************
* FunctionName : sigma_delta_setTarget
* Description : set the target (duty cycle) for the sigma-delta source
* Parameters : uint8 target, 0-255, duty cycle = target/256
* FunctionName : sigmaDeltaWrite
* Description : set the duty cycle for the sigma-delta source
* Parameters : uint8 duty, 0-255, duty cycle = target/256,
* channel = unused, for compatibility with ESP32
* Returns : none
*******************************************************************************/
void ICACHE_FLASH_ATTR sigma_delta_setTarget(uint8_t target)
void ICACHE_FLASH_ATTR sigmaDeltaWrite(uint8_t channel, uint8_t duty)
{
uint32_t reg = GPSD;
(void) channel;

reg = (reg & ~(0xFF << GPSDT)) | ((target & 0xFF) << GPSDT);
reg = (reg & ~(0xFF << GPSDT)) | ((duty & 0xFF) << GPSDT);
GPSD = reg;

}

/******************************************************************************
* FunctionName : sigma_delta_getPrescaler
* Description : get the prescaler value from the GPIO_SIGMA_DELTA register
* Parameters : none
* Returns : uint8 prescaler, CLK_DIV , 0-255
* FunctionName : sigmaDeltaRead
* Description : set the duty cycle for the sigma-delta source
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Typo here...this "get the duty..."

* Parameters : none, channel = unused, for compatibility with ESP32
* Returns : uint8_t duty cycle value 0..255
*******************************************************************************/
uint8_t ICACHE_FLASH_ATTR sigma_delta_getPrescaler(uint8_t prescaler)
uint8_t ICACHE_FLASH_ATTR sigmaDeltaRead(uint8_t channel)
{
return (uint8_t)((GPSD >> GPSDP) & 0xFF);
(void) channel;
return (uint8_t)((GPSD >> GPSDT) & 0xFF);
}

/******************************************************************************
* FunctionName : sigma_delta_setPrescaler
* FunctionName : sigmaDeltaSetPrescaler
* Description : set the clock divider for the sigma-delta source
* Parameters : uint8 prescaler, 0-255, divides the 80MHz base clock by this amount
* Returns : none
*******************************************************************************/
void ICACHE_FLASH_ATTR sigma_delta_setPrescaler(uint8_t prescaler)
void ICACHE_FLASH_ATTR sigmaDeltaSetPrescaler(uint8_t prescaler)
{
uint32_t reg = GPSD;

reg = (reg & ~(0xFF << GPSDP)) | ((prescaler & 0xFF) << GPSDP);
GPSD = reg;
}

/******************************************************************************
* FunctionName : sigmaDeltaGetPrescaler
* Description : get the prescaler value from the GPIO_SIGMA_DELTA register
* Parameters : none
* Returns : uint8 prescaler, CLK_DIV , 0-255
*******************************************************************************/
uint8_t ICACHE_FLASH_ATTR sigmaDeltaGetPrescaler(uint8_t prescaler)
{
return (uint8_t)((GPSD >> GPSDP) & 0xFF);
}
96 changes: 20 additions & 76 deletions cores/esp8266/sigma_delta.h
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Original file line number Diff line number Diff line change
Expand Up @@ -31,77 +31,16 @@ THE TARGET FREQUENCY IS DEFINED AS:

FREQ = 80,000,000/prescaler * target /256 HZ, 0<target<128
FREQ = 80,000,000/prescaler * (256-target) /256 HZ, 128<target<256
target: duty ,0-255
prescaler: clk_div,0-255
target: duty cycle,range 0-255
prescaler: is a clock divider, range 0-255
so the target and prescale will both affect the freq.
CPU_FREQ has no influence on the sigma delta frequency.

Usage :
1. sigma_delta_enable() : activate the sigma delta source with default prescalar (0) & target (0)
2. sigma_delta_attachPin(pin), any pin 0..15, TBC if gpio16 supports sigma-delta source
1. sigmaDeltaSetup(0,f) : activate the sigma delta source with frequency f and default duty cycle (0)
2. sigmaDeltaAttachPin(pin), any pin 0..15, TBC if gpio16 supports sigma-delta source
This will set the pin to NORMAL output mode (pinMode(pin,OUTPUT))
3. sigma_delta_setPrescaler(uint8_t) : reduce the output frequencies
4. sigma_delta_setTarget(uint8_t) : set the output signal duty cycle, duty cycle = target/256

5. sigma_delta_detachPin(pin), this will revert the pin to NORMAL output mode & GPIO source.
The sigma delta source remains on until :
6. sigma_delta_disable()

copy this code as example :

#include "sigma_delta.h"

void setup() {

Serial.begin(115200);
pinMode(BUILTIN_LED,OUTPUT); // blinkie & sigma-delta mix

uint32 pin = 4; //D2
sigma_delta_enable();
//sigma_delta_disable();
sigma_delta_attachPin(BUILTIN_LED);
sigma_delta_attachPin(4); // D2

sigma_delta_setPrescaler(255);

Serial.println();
Serial.println("Start Sigma Delta Example\n");
Serial.println("Attached gpio4 to the sigma delta source\n");
Serial.printf("Current target = %i, prescaler = %i\n",sigma_delta_getTarget(),sigma_delta_getPrescaler());
}

void loop() {

uint8_t target, iRepeat;

Serial.println("Attaching the built in led to the sigma delta source now\n");
Serial.printf("Current target = %i, prescaler = %i\n",sigma_delta_getTarget(),sigma_delta_getPrescaler());
sigma_delta_attachPin(BUILTIN_LED);

Serial.println("dimming builtin led...\n");
for (iRepeat=0;iRepeat<10;iRepeat++)
{
for (target=0; target<255;target=target+5)
{
sigma_delta_setTarget(target);
delay(10);
}

for (target=255; target>0;target=target-5)
{
sigma_delta_setTarget(target);
delay(10);
}

}
Serial.println("detaching builtin led & playing a blinkie\n");
sigma_delta_detachPin(BUILTIN_LED);
for (iRepeat=0;iRepeat<20;iRepeat++)
{
digitalWrite(BUILTIN_LED,!digitalRead(BUILTIN_LED));
delay(500);
}

}
3. sigmaDeltaWrite(0,dc) : set the output signal duty cycle, duty cycle = dc/256

*******************************************************************************/

Expand All @@ -112,15 +51,20 @@ void loop() {
extern "C" {
#endif

void sigma_delta_enable(void);
void sigma_delta_disable(void);
void sigma_delta_attachPin(uint8_t pin);
void sigma_delta_detachPin(uint8_t pin);
bool sigma_delta_isPinAttached(uint8_t pin);
uint8_t sigma_delta_getTarget(void);
void sigma_delta_setTarget(uint8_t target);
uint8_t sigma_delta_getPrescaler(void);
void sigma_delta_setPrescaler(uint8_t prescaler);
//channel parameter is unused (only for ESP32 compatibility) freq 1220-312500 duty 0-255
void sigmaDeltaEnable(void);
void sigmaDeltaDisable(void);
uint32_t sigmaDeltaSetup(uint8_t channel, uint32_t freq);
void sigmaDeltaWrite(uint8_t channel, uint8_t duty);
uint8_t sigmaDeltaRead(uint8_t channel = 0);
void sigmaDeltaAttachPin(uint8_t pin, uint8_t channel = 0);
void sigmaDeltaDetachPin(uint8_t pin);
bool sigmaDeltaIsPinAttached(uint8_t pin);

// alternative way to control the sigma delta generator frequency
uint8_t sigmaDeltaGetPrescaler(void);
void sigmaDeltaSetPrescaler(uint8_t prescaler);


#ifdef __cplusplus
}
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