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Volume control chip M62429 driver

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tonkostz

Joined: 07 May 2011
Posts: 54
Location: Bulgaria

Volume control chip M62429 driver

Posted: Wed Jan 01, 2025 5:15 am

I am trying to adapt an arduino driver for a olume control chip M62429 to CCS C compiler but i am not sure i understand this section of the code. Would you help on this?

Code:

// Send control word
for (uint8_t i = 0; i < 11; i++) {
delayMicroseconds (2);
digitalWrite (_pin_data, 0);
delayMicroseconds (2);
digitalWrite (_pin_clk, 0);
delayMicroseconds (2);
digitalWrite (_pin_data, (data_word >> i) & 0x01);
delayMicroseconds (2);
digitalWrite (_pin_clk, 1);
}
delayMicroseconds (2);
digitalWrite (_pin_data, 1);
delayMicroseconds (2);
digitalWrite (_pin_clk, 0);
}

This is to complete code:

Code:

/*!
* This is a library for M62429/FM62429 Serial data control dual electronics volume chips.
*
* Written by CGrassin.
*/

#include "Arduino.h"
#include "M62429.h"

M62429::M62429 (uint8_t pin_clk, uint8_t pin_data){
_pin_data = pin_data;
_pin_clk = pin_clk;
}

/*
* Sets the volume of one on both channel of the 62429.
*
* Parameters:
* attenuation, from 0 to 83dB
* both, 0 (default)=both channels or 1=individual
* channel, 0=channel 1, 1 = channel 2, no effect if both=0
*/
void M62429::_setVolume(uint8_t attenuation, uint8_t channel, uint8_t both){
uint16_t data_word = 0x00;

// Sanity checks on parameters
if(both>1 || channel>1)
return;
if(attenuation > 83)
attenuation = 83;

// Convert volume to attenuation
//uint8_t attenuation = (volume > 100) ? 0 : (((volume * 83) / -100) + 83);

// Build control word (11 bits)
data_word |= (channel << 0);          // Channel select: 0=ch1, 1=ch2
data_word |= (both << 1);          // Individual/both select: 0=both, 1=individual
data_word |= ((21 - (attenuation / 4)) << 2); // ATT1: coarse attenuator, steps of -4dB
data_word |= ((3 - (attenuation % 4)) << 7); // ATT2: fine attenuator, steps of -1dB)
data_word |= (0b11 << 9);          // 2 last bits must be 1

// Send control word
for (uint8_t i = 0; i < 11; i++) {
delayMicroseconds (2);
digitalWrite (_pin_data, 0);
delayMicroseconds (2);
digitalWrite (_pin_clk, 0);
delayMicroseconds (2);
digitalWrite (_pin_data, (data_word >> i) & 0x01);
delayMicroseconds (2);
digitalWrite (_pin_clk, 1);
}
delayMicroseconds (2);
digitalWrite (_pin_data, 1);
delayMicroseconds (2);
digitalWrite (_pin_clk, 0);
}

void M62429::setVolumeBoth(uint8_t attenuation){
_setVolume(attenuation, 0, 0);
}

void M62429::setVolumeCh1(uint8_t attenuation){
_setVolume(attenuation, 0, 1);
}

void M62429::setVolumeCh2(uint8_t attenuation){
_setVolume(attenuation, 1, 1);
}

M62429.h

Code:

/*!
* This is a library for M62429/FM62429 Serial data control dual electronics volume chips.
*
* Written by CGrassin.
*/

#ifndef M62429_H
#define M62429_H

class M62429 {
public:
M62429 (uint8_t pin_clk, uint8_t pin_data);
void setVolumeBoth(uint8_t attenuation);
void setVolumeCh1 (uint8_t attenuation);
void setVolumeCh2 (uint8_t attenuation);

private:
uint8_t _pin_data, _pin_clk;
void _setVolume(uint8_t attenuation, uint8_t channel, uint8_t both);
};

#endif

As i understood it is basically a dual digital potentiometer like MCP42xx for which i have driver. Is it possible to adapt it for this chip?
Thanks!

Ttelmah

Joined: 11 Mar 2010
Posts: 19587

Posted: Wed Jan 01, 2025 8:21 am

Read the dats sheet!.......

Seriously this is a very easy chip to drive.

All you do it clock 11 bits to the chip.

Code:

#define CLOCK_PIN pin_xx //set to what you want
#define DATA_PIN pin_yy //again set to what you want

void set_volume(unsigned int8 att, int1 chan, int1 both_flag)
{
int16 val=0x60; //Preload the upper two 1's
int8 ctr;
int16 mask=1; //mask bit
output_low(CLOCK_PIN); //ideally set this low in your initialisation
if (att1>83)
att1=83;
val |= ((21 - (att / 4L)) << 2); // ATT1: coarse attenuator, steps of
//-4dB
val |= ((3 - (att % 4L)) << 7); // ATT2: fine attenuator, steps
//of -1dB) - Note the L here, needed so the value gets extended to
//an int16 for the rotation.
if (chan)
bit_set(val,0); //channel 0/1 selection
if (both_flag)
bit_set(val,1); //If this is set will write both channels at once
for (ctr=0;ctr<11;ctr++)
{
if(mask & val)
output_high(DATA_PIN);
else
output_low(DATA_PIN);
delay_us(1);
output_high(CLOCK_PIN); //Latch the bit out.
mask*=2;
output_low(DATA_PIN);
delay_us(1);
if (ctr!=10)
output_low(DATA_PIN);
output_low(CLOCK_PIN);
delay_us(1);
}
}

I send the channel and both_flag each as one bit values, so no need
to test for these being >1.

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