Building a digital guitar effects pedal running issues that there is no sound when guitar strings or strung along with no effects I think it could be this section of my code that is causing issue since dac is constantly $0$ even hen strung this was programmed on stm$32$ cube IDE also using SPI

void Read$\_$ADC$($void$)\{$

$//$pull ADC CS low to start the conversion and start non$-$blocking SPI$2$ receive using DMA

HAL$\_$GPIO$\_$WritePin$($GPIOB$,$ GPIO$\_$PIN$\_10,$ GPIO$\_$PIN$\_$RESET$)$;

delay$\_$us$(2)$; $//2$us$,$ need at least $1\mathrm{.}4$us as per ADS$8319$ datasheet

HAL$\_$SPI$\_$Receive$\_$DMA$($&hspi$2,($uint$8\_$t$*)$&adc$\_$value, $2)$;

$\}$

$//$write DAC$8551$

void Write$\_$DAC$($uint$16\_$t dac$\_$value$)\{$

uint$8\_$t data$[3]$;

$//$the $24-$bit data as per DAC$8551$ datasheet

data$[0]=0$x$00$; $//$ Bits $23-16$: $6$ unused bits $+2$ control bits $($PD$1=0,$ PD$0=0$ for normal operation$)$

data$[1]=($dac$\_$value $>>8)$ & $0$xFF; $//$ Bits $15-8$: High byte of the $16-$bit DAC value

data$[2]=$ dac$\_$value & $0$xFF; $//$ Bits $7-0$: Low byte of the $16-$bit DAC value

$//$ Pull SYNC $($Chip Select$)$ low to start communication

HAL$\_$GPIO$\_$WritePin$($GPIOB$,$ GPIO$\_$PIN$\_12,$ GPIO$\_$PIN$\_$RESET$)$;

delay$\_$us$(1)$; $//$ Small delay for timing stabilization

$//$ Transmit the $24-$bit data over SPI

HAL$\_$SPI$\_$Transmit$\_$DMA$($&hspi$2,$ data, $3)$;

$//$ Pull SYNC $($Chip Select$)$ high to end communication

HAL$\_$GPIO$\_$WritePin$($GPIOB$,$ GPIO$\_$PIN$\_12,$ GPIO$\_$PIN$\_$SET$)$;

delay$\_$us$(1)$; $//$ Small delay for timing stabilization

$\}$

$//$apply effects parallel

void Process$\_$Audio$($void$)\{$

uint$16\_$t processedData $=$ Apply$\_$Effects$\_$Parallel$(($uint$16\_$t$*)$&adc$\_$value$)$; $//$apply all active effects

Write$\_$DAC$($processedData$)$; $//$write the processed data to DAC

$\}$

void HAL$\_$TIM$\_$PeriodElapsedCallback$($TIM$\_$HandleTypeDef $*$htim$)\{$

if $($htim$->$Instance $==$ TIM$2)\{$

$//$this interrupt occurs at $44\mathrm{.}1$ kHz

Read$\_$ADC$()$; $//$ Start ADC read

$\}$

$\}$

$//$SPI transmit

void HAL$\_$SPI$\_$TxCpltCallback$($SPI$\_$HandleTypeDef $*$hspi$)\{$

switch $(($uintptr$\_$t$)$hspi$->$Instance$)\{$

case $($uintptr$\_$t$)$SPI$1$:

HAL$\_$GPIO$\_$WritePin$($GPIOA$,$ GPIO$\_$PIN$\_4,$ GPIO$\_$PIN$\_$SET$)$; $//$ SPI$1$ specific logic

break;

case $($uintptr$\_$t$)$SPI$2$:

HAL$\_$GPIO$\_$WritePin$($GPIOB$,$ GPIO$\_$PIN$\_12,$ GPIO$\_$PIN$\_$SET$)$; $//$End transmission for SPI$2$

$//$led$\_$toggle$\_$counter$++$;

break;

$\}$

$\}$

void HAL$\_$SPI$\_$RxCpltCallback$($SPI$\_$HandleTypeDef $*$hspi$)\{$

switch $(($uintptr$\_$t$)$hspi$->$Instance$)\{$

case $($uintptr$\_$t$)$SPI$1$:

HAL$\_$GPIO$\_$WritePin$($GPIOA$,$ GPIO$\_$PIN$\_4,$ GPIO$\_$PIN$\_$SET$)$; $//$ SPI$1$ specific logic

break;

case $($uintptr$\_$t$)$SPI$2$:

HAL$\_$GPIO$\_$WritePin$($ADC$\_$CSn$\_$GPIO$\_$Port, ADC$\_$CSn$\_$Pin, GPIO$\_$PIN$\_$SET$)$;$//$deselect adc

adc$\_$ready $=$ true;

break;

$\}$

$\}$

$//$for $1\mathrm{.}4$us Conversion Time per ADC datasheet

void delay$\_$us$($uint$32\_$t us$)\{$

uint$32\_$t tickstart $=$ HAL$\_$GetTick$()$; $//$ HAL tick is usually in milliseconds

while $(($HAL$\_$GetTick$()-$ tickstart$)<($us $/1000))$; $//$ Microsecond approximation

$\}$

$//$record audio

void Record$\_$Audio$($void$)\{$

if $($adc$\_$ready$)\{$

adc$\_$ready $=$ false;

$//$add ADC value to buffer

audioBuffer$[$bufferWriteIndex$++]=$ adc$\_$value;

if $($bufferWriteIndex $>=$ BUFFER$\_$SIZE$)\{$

bufferWriteIndex $=0$; $//$wrap around to maintain circular buffer

$\}$

bufferCount$++$;

$//$if buffer is half or completely full, write to flash

if $($bufferCount $>=$ PAGE$\_$SIZE$)\{$

WriteBufferedDataToFlash$()$;

$\}$

$//$start the next ADC conversion

Read$\_$ADC$()$;

$\}$

$\}$