Error in input_tdm.cpp and input_tdm2.cpp

[palmerr23]

Description

When a device that uses 16 bit TDM slots is connected, input data is corrupted on the all odd numbered channels. The issue is not revealed with 32-bit slots as the odd channels are ignored.

This is because of an incorrect calculation on line 102:

*dest2++ = (in1 << 16) | (in2 & 0x0000FFFF);

This code swaps the samples, putting the first sample in the high part, and the second sample in the low part of the 32-bit destination word. This is opposite to the behaviour of dest1 on line 101:

*dest1++ = (in1 >> 16) | (in2 & 0xFFFF0000);

the solution is to substitute line 102 with this line of code in both files:

*dest2++ = (in1 & 0x0000FFFF) | (in2 << 16);

The solution has been tested on CS42448 and TLV320AIC3104 hardware in TDM mode.

Steps To Reproduce Problem

16-bit TDM hardware is required, such as my new 4xTLV320AIC3104 board.

Any code that inputs L&R TDM channels will work.

Hardware & Software

Board
T4.0
Shields / modules used New
TLV320AIC3104 board
Arduino IDE version
2.3.2
Teensyduino version
1.59
Operating system & version
Win11
Any other software or hardware?

Arduino Sketch

#include <Audio.h>
#include <Wire.h>
#include <SPI.h>
#include <SD.h>
#include <SerialFlash.h>
#include "control_tlv320aic3104.h"

#define BLOX 40
AudioInputTDM tdm1;
AudioOutputUSB usb1;
AudioConnection patchCord15(tdm1, 0, usb1, 0);
AudioConnection patchCord16(tdm1, 1, usb1, 1);
AudioControlTLV320AIC3104 aic;

void setup()
{
AudioMemory(BLOX);
Wire.begin();

aic.audioMode(4, true, AICMODE_TDM);
aic.inputMode(AIC_SINGLE);
aic.enable( );
aic.gain(0);
}

void loop()
{
}

Errors or Incorrect Output

Right channel input shows a spike at (22.05 -f) kHz, with an amplitude that varies with the input.

Left

Right

[h4yn0nnym0u5e]

This is fixed in #440

[palmerr23]

Thanks Jonathan for the update - I've also just posted a PR. Hopefully PS will get around to merging one of them in the near future.

See PRs 440 and 480

[h4yn0nnym0u5e]

Hopefully ... #440 is over 2 years old, but maybe Teensyduino 1.60 will involve some massive Audio library housekeeping

[palmerr23]

PR 440 has now been merged.