diff --git a/Makefile b/Makefile
index 1094e23..16f0ced 100644
--- a/Makefile
+++ b/Makefile
@@ -93,6 +93,7 @@ SRC = main.c \
 	$(HALS)/stm32f7xx_hal_pwr.c \
 	$(HALS)/stm32f7xx_hal_pwr_ex.c \
 	$(HALS)/stm32f7xx_hal_rng.c \
+	$(HALS)/stm32f7xx_hal_sai.c \
 	$(HALS)/stm32f7xx_hal_spi.c \
 	$(HALS)/stm32f7xx_hal_tim.c \
 	$(HALS)/stm32f7xx_hal_tim_ex.c \
diff --git a/lib/flash.h b/lib/flash.h
index 645f2ef..a1890a5 100644
--- a/lib/flash.h
+++ b/lib/flash.h
@@ -2,17 +2,17 @@
 
 #include "stm32f7xx.h"
 
-// 16kB calibration
-#define CALIBRATION_LOCATION 0x0800C000
-#define CALIBRATION_SECTOR   FLASH_SECTOR_3
-#define CALIBRATION_SIZE     (0x4000 - 4)
-
-// 64kB user script
-#define USER_SCRIPT_LOCATION 0x08010000
-#define USER_SCRIPT_SECTOR   FLASH_SECTOR_4
+// 16kB calibration -> using 256kB
+#define CALIBRATION_LOCATION 0x08180000
+#define CALIBRATION_SECTOR   FLASH_SECTOR_10 // UNUSED
+#define CALIBRATION_SIZE     (0x40000 - 4)
+
+// 64kB user script -> using 256kB
+#define USER_SCRIPT_LOCATION 0x081C0000
+#define USER_SCRIPT_SECTOR   FLASH_SECTOR_11
 //#define USER_SCRIPT_SIZE     (0x10000 - 4)
 // #define USER_SCRIPT_SIZE     (0x2000 - 4) // 8kB up to v2.1
-#define USER_SCRIPT_SIZE     (0x4000 - 4) // 16kB v3.0+
+#define USER_SCRIPT_SIZE     (0x40000 - 4) // 16kB v3.0+
 
 typedef enum { FLASH_Status_Init  = 0
              , FLASH_Status_Saved = 1
diff --git a/lib/slopes.h b/lib/slopes.h
index 6ad7b8b..dd8ef2c 100644
--- a/lib/slopes.h
+++ b/lib/slopes.h
@@ -39,7 +39,7 @@ typedef struct{
     float shaped; // current shaped output voltage
 } Slope_t;
 
-#define SLOPE_CHANNELS 4
+#define SLOPE_CHANNELS 8
 
 // refactor for dynamic SLOPE_CHANNELS
 // refactor for dynamic SAMPLE_RATE
diff --git a/ll/adda.c b/ll/adda.c
index fb7647e..20558f3 100644
--- a/ll/adda.c
+++ b/ll/adda.c
@@ -5,7 +5,8 @@
 
 #include "debug_pin.h"
 #include "ads131.h"
-#include "dac8565.h"
+// #include "dac8565.h"
+#include "dac108.h"
 
 #include "../lib/flash.h"              // FLASH_*_t
 #include "cal_ll.h"      // CAL_LL_Init(),
@@ -28,15 +29,15 @@ static void CAL_ReadFlash( void );
 
 uint16_t ADDA_Init( int adc_timer_ix )
 {
-    ADC_Init( ADDA_BLOCK_SIZE
-            , ADDA_ADC_CHAN_COUNT
-            , adc_timer_ix
-            );
+    // ADC_Init( ADDA_BLOCK_SIZE
+    //         , ADDA_ADC_CHAN_COUNT
+    //         , adc_timer_ix
+    //         );
     DAC_Init( ADDA_BLOCK_SIZE
             , ADDA_DAC_CHAN_COUNT
             );
-    CAL_LL_Init();
-    CAL_ReadFlash();
+    // CAL_LL_Init();
+    // CAL_ReadFlash();
     return ADDA_BLOCK_SIZE;
 }
 
@@ -45,12 +46,12 @@ void ADDA_Start( void )
     DAC_Start();
 }
 
-void ADDA_BlockProcess( uint32_t* dac_pickle_ptr )
+static IO_block_t b = { .size = ADDA_BLOCK_SIZE };
+void ADDA_BlockProcess( uint16_t* dac_pickle_ptr )
 {
-    IO_block_t b = { .size = ADDA_BLOCK_SIZE };
-    ADC_UnpickleBlock( b.in[0]
-                     , ADDA_BLOCK_SIZE
-                     );
+    // ADC_UnpickleBlock( b.in[0]
+    //                  , ADDA_BLOCK_SIZE
+    //                  );
     IO_BlockProcess( &b );
     DAC_PickleBlock( dac_pickle_ptr
                    , b.out[0]
@@ -60,16 +61,16 @@ void ADDA_BlockProcess( uint32_t* dac_pickle_ptr )
 
 float ADDA_GetADCValue( uint8_t channel )
 {
-    return ADC_GetValue( channel );
+    return 0.0;
+    // return ADC_GetValue( channel );
 }
 
 __weak IO_block_t* IO_BlockProcess( IO_block_t* b )
 {
     for( uint16_t i=0; i<(b->size); i++ ){
-        b->out[0][i] = b->in[0][i];
-        b->out[1][i] = b->in[1][i];
-        b->out[2][i] = 2.0;
-        b->out[3][i] = 3.0;
+        for(int j=0; j<8; j++){
+            b->out[j][i] = 0.0;
+        }
     }
     return b;
 }
@@ -98,10 +99,10 @@ void CAL_Set( int chan, CAL_Param_t param, float val )
     if(chan >= 1 && chan <= 2){ // adc
         if(param == CAL_Offset){
             cal.adc[chan-1].shift = val;
-            ADC_CalibrateShift(chan-1, val);
+            // ADC_CalibrateShift(chan-1, val);
         } else {
             cal.adc[chan-1].scale = val;
-            ADC_CalibrateScalar(chan-1, val);
+            // ADC_CalibrateScalar(chan-1, val);
         }
     } else if( chan >= 3 && chan <= 6){ // dac
         if(param == CAL_Offset){
@@ -145,8 +146,9 @@ static void CAL_ReadFlash( void )
                                , sizeof(CAL_chan_t) * (2+4)
                                ) ){
         for( int j=0; j<2; j++ ){
-            ADC_CalibrateShift( j, cal.adc[j].shift );
-            ADC_CalibrateScalar( j, cal.adc[j].scale );
+            ;;
+            // ADC_CalibrateShift( j, cal.adc[j].shift );
+            // ADC_CalibrateScalar( j, cal.adc[j].scale );
         }
         for( int j=0; j<4; j++ ){
             DAC_CalibrateOffset( j, cal.dac[j].shift );
@@ -154,6 +156,6 @@ static void CAL_ReadFlash( void )
         }
     } else {
         printf("not yet calibrated\n");
-        CAL_Defaults();
+        // CAL_Defaults();
     }
 }
diff --git a/ll/dac108.c b/ll/dac108.c
index 9c1797b..f62a2d2 100644
--- a/ll/dac108.c
+++ b/ll/dac108.c
@@ -15,7 +15,7 @@ uint16_t* samples = NULL;
 
 #define DAC_ZERO_VOLTS      ((uint16_t)(((uint32_t)0xFFFF * 2)/3))
 #define DAC_V_TO_U16        ((float)(65535.0 / 15.0))
-#define DAC_CHANNELSS 4
+#define DAC_CHANNELSS 8
 float dac_calibrated_offset[DAC_CHANNELSS];
 float dac_calibrated_scalar[DAC_CHANNELSS];
 
@@ -26,15 +26,16 @@ void DAC_Init(uint16_t bsize, uint8_t chan_count){
     sai_init();
 
     // Create the sample buffer for DMA transfer
-    samp_count = DAC_BUFFER_COUNT * bsize * chan_count;
-    samples = malloc( sizeof(uint16_t) * samp_count );
-    for( int i=0; i<samp_count; i++ ){ samples[i] = 0; } // unnecessary
+    samp_count = DAC_BUFFER_COUNT * bsize * chan_count; // 512
+    printf("samp_count %x\n\r", samp_count);
+    samples = malloc( sizeof(uint16_t) * samp_count ); // 1k
     if(samples == NULL){ printf("!DAC_buffer\n"); }
+    for( int i=0; i<samp_count; i++ ){ samples[i] = 0; } // unnecessary
 
-    for( int j=0; j<DAC_CHANNELSS; j++ ){
-        dac_calibrated_offset[j] = 0.0;
-        dac_calibrated_scalar[j] = DAC_V_TO_U16;
-    }
+    // for( int j=0; j<DAC_CHANNELSS; j++ ){
+    //     dac_calibrated_offset[j] = 0.0;
+    //     dac_calibrated_scalar[j] = DAC_V_TO_U16;
+    // }
 }
 
 void DAC_Start(void){
@@ -132,7 +133,7 @@ static void sai_init(void){
     hsai_a.Init.FirstBit          = SAI_FIRSTBIT_MSB;
     hsai_a.Init.ClockStrobing     = SAI_CLOCKSTROBING_RISINGEDGE; // CONFIRM
 
-    hsai_a.FrameInit.FrameLength          = 8; // was 33 for 32 vals
+    hsai_a.FrameInit.FrameLength          = 17; // was 33 for 32 vals
     hsai_a.FrameInit.ActiveFrameLength    = 1; // 1 ?
     hsai_a.FrameInit.FSDefinition         = SAI_FS_STARTFRAME;
     hsai_a.FrameInit.FSPolarity           = SAI_FS_ACTIVE_HIGH;
@@ -141,9 +142,13 @@ static void sai_init(void){
     hsai_a.SlotInit.FirstBitOffset    = 0;
     hsai_a.SlotInit.SlotSize          = SAI_SLOTSIZE_16B;
     hsai_a.SlotInit.SlotNumber        = 8;
-    hsai_a.SlotInit.SlotActive        = SAI_SLOTACTIVE_ALL;
+    hsai_a.SlotInit.SlotActive        = SAI_SLOTACTIVE_0 | SAI_SLOTACTIVE_1
+                                      | SAI_SLOTACTIVE_2 | SAI_SLOTACTIVE_3
+                                      | SAI_SLOTACTIVE_4 | SAI_SLOTACTIVE_5
+                                      | SAI_SLOTACTIVE_6 | SAI_SLOTACTIVE_7;
 
     if(HAL_SAI_Init(&hsai_a)){
+        printf("sai init failed\n\r");
         return;
     }
 
@@ -182,7 +187,7 @@ void HAL_SAI_MspInit(SAI_HandleTypeDef *hsai)
     hdma_tx_a.Init.Mode                   = DMA_CIRCULAR;
     hdma_tx_a.Init.Priority               = DMA_PRIORITY_HIGH;
     hdma_tx_a.Init.FIFOMode               = DMA_FIFOMODE_DISABLE;
-    hdma_tx_a.Init.FIFOThreshold          = DMA_FIFO_THRESHOLD_FULL;
+    hdma_tx_a.Init.FIFOThreshold          = DMA_FIFO_THRESHOLD_1QUARTERFULL;
     hdma_tx_a.Init.MemBurst               = DMA_MBURST_SINGLE;
     hdma_tx_a.Init.PeriphBurst            = DMA_PBURST_SINGLE;
 
@@ -199,11 +204,18 @@ void HAL_SAI_MspInit(SAI_HandleTypeDef *hsai)
         // debug(&debug, "HAL_DMA_Init failed");
         return;
     }
+
+    // Codec request triggers transfer & new frame calc
+    HAL_NVIC_SetPriority( DMA2_Stream3_IRQn
+                        , DAC_IRQPriority
+                        , 1
+                        );
+    HAL_NVIC_EnableIRQ( DMA2_Stream3_IRQn );
 }
 
 void sai_start_transmit(uint16_t* hwords, uint16_t count){
     if(HAL_SAI_Transmit_DMA(&hsai_a, (uint8_t*)hwords, count)){
-        ;
+        printf("sai transmit fail.\n\r");
     }
 }
 
@@ -212,6 +224,9 @@ void sai_start_transmit(uint16_t* hwords, uint16_t count){
 // DMA triggered by codec requesting more ADC!
 void DMA2_Stream3_IRQHandler(void){
     HAL_DMA_IRQHandler(&hdma_tx_a);
+    if(hdma_tx_a.ErrorCode != HAL_OK){
+        printf("sai dma err: 0x%0x\n\r", hdma_tx_a.ErrorCode);
+    }
 }
 
 static void callback(int offset){
@@ -222,7 +237,13 @@ static void callback(int offset){
     // float out[b_size2];
     // codec_to_floats( in, &in[b_size], &inBuff[offset2], b_size );
 // FIXME ONLY ONE OF THE NEXT 2 FUNS
+
     ADDA_BlockProcess( samples );
+
+
+
+
+
     // (*block_process_fn)( out
     //                    , in // treat ins as zeroes (unused)
     //                    , b_size
@@ -233,5 +254,7 @@ static void callback(int offset){
 
 void HAL_SAI_TxHalfCpltCallback(SAI_HandleTypeDef *hsai){ callback(0); }
 void HAL_SAI_TxCpltCallback(SAI_HandleTypeDef *hsai){ callback(1); }
-
+void HAL_SAI_ErrorCallback(SAI_HandleTypeDef *hsai){
+    printf("sai error 0x%x\n\r", hsai->ErrorCode);
+}
 
diff --git a/ll/dac108.h b/ll/dac108.h
index befc88e..507b317 100644
--- a/ll/dac108.h
+++ b/ll/dac108.h
@@ -3,53 +3,6 @@
 #include <stm32f7xx.h>
 #include "interrupts.h" // DAC_IRQPriority
 
-// Defn for I2S
-#define I2Sx                             SPI2
-#define I2Sx_CLK_ENABLE()                __HAL_RCC_SPI2_CLK_ENABLE()
-#define I2Sx_DMAx_CLK_ENABLE()           __HAL_RCC_DMA1_CLK_ENABLE()
-#define I2Sx_NSS_GPIO_CLK_ENABLE()       __HAL_RCC_GPIOB_CLK_ENABLE()
-#define I2Sx_SCK_GPIO_CLK_ENABLE()       __HAL_RCC_GPIOB_CLK_ENABLE()
-#define I2Sx_MOSI_GPIO_CLK_ENABLE()      __HAL_RCC_GPIOB_CLK_ENABLE()
-#define I2Sx_NRST_GPIO_CLK_ENABLE()      __HAL_RCC_GPIOB_CLK_ENABLE()
-
-#define I2Sx_FORCE_RESET()               __HAL_RCC_SPI2_FORCE_RESET()
-#define I2Sx_RELEASE_RESET()             __HAL_RCC_SPI2_RELEASE_RESET()
-
-// Definition for I2Sx Pins
-#define I2Sx_NSS_PIN                     GPIO_PIN_12
-#define I2Sx_NSS_GPIO_PORT               GPIOB
-#define I2Sx_NSS_AF                      GPIO_AF5_SPI2
-#define I2Sx_SCK_PIN                     GPIO_PIN_13
-#define I2Sx_SCK_GPIO_PORT               GPIOB
-#define I2Sx_SCK_AF                      GPIO_AF5_SPI2
-#define I2Sx_MOSI_PIN                    GPIO_PIN_15
-#define I2Sx_MOSI_GPIO_PORT              GPIOB
-#define I2Sx_MOSI_AF                     GPIO_AF5_SPI2
-#define I2Sx_NRST_PIN                    GPIO_PIN_14
-#define I2Sx_NRST_GPIO_PORT              GPIOB
-
-// Definition for SPId's DMA
-#define I2Sx_TX_DMA_CHANNEL              DMA_CHANNEL_0
-#define I2Sx_TX_DMA_STREAM               DMA1_Stream4
-
-// Definition for SPId's NVIC
-#define I2Sx_IRQn                        SPI2_IRQn
-#define I2Sx_IRQHandler                  SPI2_IRQHandler
-#define I2Sx_DMA_TX_IRQn                 DMA1_Stream4_IRQn
-#define I2Sx_DMA_TX_IRQHandler           DMA1_Stream4_IRQHandler
-
-#define I2Sx_IRQPriority             DAC_IRQPriority
-#define I2Sx_IRQSubPriority          2
-#define I2Sx_DMA_TX_IRQPriority      DAC_IRQPriority
-#define I2Sx_DMA_TX_IRQSubPriority   1
-
-// dac8565 defines
-#define DAC8565_SET_ONE        ((uint8_t)0b00010000)
-#define DAC8565_PREP_ONE       ((uint8_t)0x0)
-#define DAC8565_SET_AND_UPDATE ((uint8_t)0b00100000)
-#define DAC8565_SET_ALL        ((uint8_t)0b00110100)
-#define DAC8565_REFRESH_ALL    ((uint8_t)0b00110000)
-
 void DAC_Init( uint16_t bsize, uint8_t chan_count );
 void DAC_Start(void);
 
@@ -60,13 +13,6 @@ void DAC_PickleBlock( uint16_t* dac_pickle_ptr
                     , uint16_t  bsize
                     );
 
-void I2Sx_DMA_TX_IRQHandler(void);
-void I2Sx_IRQHandler(void);
-
-void HAL_I2S_TxCpltCallback( I2S_HandleTypeDef *hi2s );
-void HAL_I2S_TxHalfCpltCallback( I2S_HandleTypeDef *hi2s );
-void HAL_I2S_ErrorCallback( I2S_HandleTypeDef *hi2s );
-
 void DAC_I2S_MspInit(I2S_HandleTypeDef *hi2s);
 void DAC_I2S_MspDeInit(I2S_HandleTypeDef *hi2s);
 
@@ -78,3 +24,4 @@ void HAL_SAI_MspInit(SAI_HandleTypeDef *hsai);
 void DMA2_Stream3_IRQHandler(void);
 void HAL_SAI_TxHalfCpltCallback(SAI_HandleTypeDef *hsai);
 void HAL_SAI_TxCpltCallback(SAI_HandleTypeDef *hsai);
+void HAL_SAI_ErrorCallback(SAI_HandleTypeDef *hsai);
diff --git a/ll/dac8565.c b/ll/dac8565.c
deleted file mode 100644
index ce2a704..0000000
--- a/ll/dac8565.c
+++ /dev/null
@@ -1,284 +0,0 @@
-/*#include "dac8565.h"
-
-#include <stdio.h>
-#include "stdlib.h" // malloc()
-#include "debug_pin.h"
-
-#include "adda.h"   // ADDA_BlockProcess()
-#include "wrMath.h" // lim_f()
-
-#define DAC_BUFFER_COUNT 2 // ping-pong
-
-I2S_HandleTypeDef dac_i2s;
-
-// pointer to the malloc()d buffer from DAC_Init()
-uint32_t  samp_count = 0;
-uint32_t* samples = NULL;
-
-#define DAC_ZERO_VOLTS      ((uint16_t)(((uint32_t)0xFFFF * 2)/3))
-#define DAC_V_TO_U16        ((float)(65535.0 / 15.0))
-#define DAC_CHANNELSS 4
-float dac_calibrated_offset[DAC_CHANNELSS];
-float dac_calibrated_scalar[DAC_CHANNELSS];
-
-void DAC_Init( uint16_t bsize, uint8_t chan_count )
-{
-    // Create the sample buffer for DMA transfer
-    samp_count = DAC_BUFFER_COUNT * bsize * chan_count;
-    samples = malloc( sizeof(uint32_t) * samp_count );
-    for( int i=0; i<samp_count; i++ ){ samples[i] = 0; } // unnecessary
-    if(samples == NULL){ printf("DAC_buffer\n"); }
-
-    for( int j=0; j<DAC_CHANNELSS; j++ ){
-        dac_calibrated_offset[j] = 0.0;
-        dac_calibrated_scalar[j] = DAC_V_TO_U16;
-    }
-
-    // Set the SPI parameters
-    dac_i2s.Instance          = I2Sx;
-    dac_i2s.Init.Mode         = I2S_MODE_MASTER_TX;
-    dac_i2s.Init.Standard     = I2S_STANDARD_PCM_SHORT;
-    dac_i2s.Init.DataFormat   = I2S_DATAFORMAT_24B;
-    dac_i2s.Init.MCLKOutput   = I2S_MCLKOUTPUT_ENABLE;
-    dac_i2s.Init.AudioFreq    = I2S_AUDIOFREQ_192K; // manipulates mclk to hit 48kHz on 4 chans
-    dac_i2s.Init.CPOL         = I2S_CPOL_LOW;
-    dac_i2s.Init.ClockSource  = I2S_CLOCK_PLL;
-
-    if(HAL_I2S_Init(&dac_i2s) != HAL_OK){ printf("i2s_init\n"); }
-
-    // NRST & NSS both high
-    HAL_GPIO_WritePin( I2Sx_NRST_GPIO_PORT, I2Sx_NRST_PIN, 0 );
-    volatile uint32_t t=10000; while(t){t--;}
-    HAL_GPIO_WritePin( I2Sx_NRST_GPIO_PORT, I2Sx_NRST_PIN, 1 );
-}
-
-// Initialize the DMA buffer to contain required metadata
-// Each channel is initialized with its relevant SPI command
-// The last channel latches all the new values to the outputs
-//
-//
-void DAC_Start(void)
-{
-    // prepare SPI packet metadata
-    uint32_t* dbuf = samples;
-    for( uint16_t i=0; i<samp_count; i++ ){
-        uint8_t* addr_ptr = ((uint8_t*)dbuf) + 1;
-        *addr_ptr = (i%4 == 3)
-                        ? DAC8565_SET_AND_UPDATE | 3 << 1
-                        : DAC8565_PREP_ONE | (i%4) << 1;
-        dbuf++;
-    }
-
-    // set all channels to 0v (0xAAAA)
-    dbuf = samples;
-    for( uint16_t i=0; i<samp_count; i++ ){
-        uint8_t* addr_ptr = ((uint8_t*)dbuf) + 0;
-        *addr_ptr = 0xAA;
-        addr_ptr += 3;
-        *addr_ptr = 0xAA;
-        dbuf++;
-    }
-    // begin i2s transmission
-    int error;
-    BLOCK_IRQS(
-        error = HAL_I2S_Transmit_DMA( &dac_i2s
-                            , (uint16_t*)samples
-                            , samp_count
-                            );
-    );
-    if(error){ printf("i2s failed to start\n"); }
-}
-
-void DAC_CalibrateScalar( uint8_t channel, float scale )
-{
-    dac_calibrated_scalar[channel] = DAC_V_TO_U16 * scale;
-}
-
-void DAC_CalibrateOffset( uint8_t channel, float volts )
-{
-    dac_calibrated_offset[channel] = volts;
-}
-
-int32_t lim_i32_u16( int32_t v )
-{
-    return (v > (int32_t)(uint16_t)0xFFFF) ? 0xFFFF : (v < (int32_t)0) ? 0 : v;
-}
-
-// does all the work converting a generic representation into serial packets
-// convert floats (representing volts) to u16 representation
-// Interleave a block of each channel into a stream
-
-void DAC_PickleBlock( uint32_t* dac_pickle_ptr
-                    , float*    unpickled_data
-                    , uint16_t  bsize
-                    )
-{
-    for( uint8_t j=0; j<4; j++ ){
-        add_vf_f( &(unpickled_data[j*bsize])
-                , dac_calibrated_offset[j]
-                , &(unpickled_data[j*bsize])
-                , bsize
-                );
-    }
-    for( uint8_t j=0; j<4; j++ ){
-        mul_vf_f( &(unpickled_data[j*bsize])
-                , dac_calibrated_scalar[j] // scale volts up to u16
-                , bsize
-                );
-    }
-
-    uint16_t usixteens[bsize * 4];
-    uint16_t* usixp = usixteens;
-
-    for( uint16_t i=0; i<bsize; i++ ){
-        for( uint8_t j=0; j<4; j++ ){
-            *usixp++ = (uint16_t)lim_i32_u16( DAC_ZERO_VOLTS
-                                   //- (int32_t)(*u[j]++)
-                                   - (int32_t)(unpickled_data[i+j*bsize])
-                                 );
-        }
-    }
-
-    uint8_t* insert_p = (uint8_t*)dac_pickle_ptr;
-    usixp = usixteens;
-
-    for( uint16_t i=0; i<(bsize*4); i++ ){
-        *insert_p = *usixp>>8;
-        insert_p += 3;
-        *insert_p++ = *usixp++ & 0xFF;
-    }
-}
-
-
-
-// This wraps the (un)pickling functions in ll/addac.c
-void HAL_I2S_TxHalfCpltCallback( I2S_HandleTypeDef *hi2s )
-{
-    Debug_Pin_Set(1);
-    ADDA_BlockProcess( samples );
-    Debug_Pin_Set(0);
-}
-void HAL_I2S_TxCpltCallback( I2S_HandleTypeDef *hi2s )
-{
-    Debug_Pin_Set(1);
-    ADDA_BlockProcess( &samples[samp_count/2] );
-    Debug_Pin_Set(0);
-}
-void HAL_I2S_ErrorCallback( I2S_HandleTypeDef *hi2s )
-{
-    printf("i2s_tx_error\n");
-}
-
-
-// Driver Config
-void HAL_I2S_MspInit(I2S_HandleTypeDef *hi2s)
-{
-    // I2S PLL Config
-    RCC_PeriphCLKInitTypeDef RCC_ExCLKInitStruct;
-
-    // PLLI2S_VCO = f(VCO clock) = f(PLLI2S clock input) × (PLLI2SN/PLLM)
-    // I2SCLK = f(PLLI2S clock output) = f(VCO clock) / PLLI2SR
-    RCC_ExCLKInitStruct.PeriphClockSelection = RCC_PERIPHCLK_I2S;
-    RCC_ExCLKInitStruct.I2sClockSelection = RCC_I2SCLKSOURCE_PLLI2S;
-    RCC_ExCLKInitStruct.PLLI2S.PLLI2SN = 384; // mul factor: 50~432
-    RCC_ExCLKInitStruct.PLLI2S.PLLI2SR = 2; // div factor: 2~7
-    HAL_RCCEx_PeriphCLKConfig(&RCC_ExCLKInitStruct);
-
-    // SPI/I2S & DMA
-    I2Sx_CLK_ENABLE();
-    I2Sx_DMAx_CLK_ENABLE();
-
-    // GPIO pins
-    I2Sx_NSS_GPIO_CLK_ENABLE();
-    I2Sx_SCK_GPIO_CLK_ENABLE();
-    I2Sx_MOSI_GPIO_CLK_ENABLE();
-    I2Sx_NRST_GPIO_CLK_ENABLE();
-
-    GPIO_InitTypeDef  GPIO_InitStruct;
-
-    GPIO_InitStruct.Pin       = I2Sx_SCK_PIN;
-    GPIO_InitStruct.Speed     = GPIO_SPEED_FAST;
-    GPIO_InitStruct.Mode      = GPIO_MODE_AF_PP;
-    GPIO_InitStruct.Alternate = I2Sx_SCK_AF;
-    HAL_GPIO_Init(I2Sx_SCK_GPIO_PORT, &GPIO_InitStruct);
-
-    GPIO_InitStruct.Pin       = I2Sx_MOSI_PIN;
-    GPIO_InitStruct.Alternate = I2Sx_MOSI_AF;
-    HAL_GPIO_Init(I2Sx_MOSI_GPIO_PORT, &GPIO_InitStruct);
-
-    GPIO_InitStruct.Pin       = I2Sx_NSS_PIN;
-    GPIO_InitStruct.Alternate = I2Sx_NSS_AF;
-    HAL_GPIO_Init(I2Sx_NSS_GPIO_PORT, &GPIO_InitStruct);
-
-    // NRST handled manually
-    GPIO_InitStruct.Pin       = I2Sx_NRST_PIN;
-    GPIO_InitStruct.Pull      = GPIO_PULLUP;
-    GPIO_InitStruct.Mode      = GPIO_MODE_OUTPUT_PP;
-    HAL_GPIO_Init(I2Sx_NRST_GPIO_PORT, &GPIO_InitStruct);
-
-    // DMA Streams
-    static DMA_HandleTypeDef hdma_tx;
-
-    hdma_tx.Instance                 = I2Sx_TX_DMA_STREAM;
-
-    hdma_tx.Init.Channel             = I2Sx_TX_DMA_CHANNEL;
-    hdma_tx.Init.Direction           = DMA_MEMORY_TO_PERIPH;
-    hdma_tx.Init.PeriphInc           = DMA_PINC_DISABLE;
-    hdma_tx.Init.MemInc              = DMA_MINC_ENABLE;
-    hdma_tx.Init.PeriphDataAlignment = DMA_PDATAALIGN_HALFWORD;
-    hdma_tx.Init.MemDataAlignment    = DMA_MDATAALIGN_WORD;
-    hdma_tx.Init.Mode                = DMA_CIRCULAR;
-    hdma_tx.Init.Priority            = DMA_PRIORITY_LOW;
-    hdma_tx.Init.FIFOMode            = DMA_FIFOMODE_DISABLE;
-    hdma_tx.Init.FIFOThreshold       = DMA_FIFO_THRESHOLD_FULL;
-    hdma_tx.Init.MemBurst            = DMA_MBURST_INC4;
-    hdma_tx.Init.PeriphBurst         = DMA_PBURST_INC4;
-
-    HAL_DMA_Init(&hdma_tx);
-
-    // Associate I2S w/ DMA
-    __HAL_LINKDMA(hi2s, hdmatx, hdma_tx);
-
-    // DMA Priority (should be below IO, but above main process)
-    HAL_NVIC_SetPriority( I2Sx_DMA_TX_IRQn
-                        , I2Sx_DMA_TX_IRQPriority
-                        , I2Sx_DMA_TX_IRQSubPriority
-                        );
-    HAL_NVIC_EnableIRQ( I2Sx_DMA_TX_IRQn );
-
-    // Must be lower priority than the above DMA
-    HAL_NVIC_SetPriority( I2Sx_IRQn
-                        , I2Sx_IRQPriority
-                        , I2Sx_IRQSubPriority
-                        );
-    HAL_NVIC_EnableIRQ( I2Sx_IRQn );
-}
-
-void DAC_I2S_MspDeInit(I2S_HandleTypeDef *hi2s)
-{
-
-  static DMA_HandleTypeDef hdma_tx;
-
-  I2Sx_FORCE_RESET();
-  I2Sx_RELEASE_RESET();
-
-  HAL_GPIO_DeInit(I2Sx_NSS_GPIO_PORT,  I2Sx_NSS_PIN);
-  HAL_GPIO_DeInit(I2Sx_SCK_GPIO_PORT,  I2Sx_SCK_PIN);
-  HAL_GPIO_DeInit(I2Sx_MOSI_GPIO_PORT, I2Sx_MOSI_PIN);
-
-  HAL_DMA_DeInit(&hdma_tx);
-
-  HAL_NVIC_DisableIRQ(I2Sx_DMA_TX_IRQn);
-  HAL_NVIC_DisableIRQ(I2Sx_IRQn);
-}
-
-void I2Sx_DMA_TX_IRQHandler(void)
-{
-    HAL_DMA_IRQHandler(dac_i2s.hdmatx);
-}
-void I2Sx_IRQHandler(void)
-{
-    HAL_I2S_IRQHandler(&dac_i2s);
-}
-
-*/
diff --git a/ll/dac8565.h b/ll/dac8565.h
deleted file mode 100644
index 8fbe45f..0000000
--- a/ll/dac8565.h
+++ /dev/null
@@ -1,74 +0,0 @@
-#pragma once
-
-/*
-#include <stm32f7xx.h>
-#include "interrupts.h" // DAC_IRQPriority
-
-// Defn for I2S
-#define I2Sx                             SPI2
-#define I2Sx_CLK_ENABLE()                __HAL_RCC_SPI2_CLK_ENABLE()
-#define I2Sx_DMAx_CLK_ENABLE()           __HAL_RCC_DMA1_CLK_ENABLE()
-#define I2Sx_NSS_GPIO_CLK_ENABLE()       __HAL_RCC_GPIOB_CLK_ENABLE()
-#define I2Sx_SCK_GPIO_CLK_ENABLE()       __HAL_RCC_GPIOB_CLK_ENABLE()
-#define I2Sx_MOSI_GPIO_CLK_ENABLE()      __HAL_RCC_GPIOB_CLK_ENABLE()
-#define I2Sx_NRST_GPIO_CLK_ENABLE()      __HAL_RCC_GPIOB_CLK_ENABLE()
-
-#define I2Sx_FORCE_RESET()               __HAL_RCC_SPI2_FORCE_RESET()
-#define I2Sx_RELEASE_RESET()             __HAL_RCC_SPI2_RELEASE_RESET()
-
-// Definition for I2Sx Pins
-#define I2Sx_NSS_PIN                     GPIO_PIN_12
-#define I2Sx_NSS_GPIO_PORT               GPIOB
-#define I2Sx_NSS_AF                      GPIO_AF5_SPI2
-#define I2Sx_SCK_PIN                     GPIO_PIN_13
-#define I2Sx_SCK_GPIO_PORT               GPIOB
-#define I2Sx_SCK_AF                      GPIO_AF5_SPI2
-#define I2Sx_MOSI_PIN                    GPIO_PIN_15
-#define I2Sx_MOSI_GPIO_PORT              GPIOB
-#define I2Sx_MOSI_AF                     GPIO_AF5_SPI2
-#define I2Sx_NRST_PIN                    GPIO_PIN_14
-#define I2Sx_NRST_GPIO_PORT              GPIOB
-
-// Definition for SPId's DMA
-#define I2Sx_TX_DMA_CHANNEL              DMA_CHANNEL_0
-#define I2Sx_TX_DMA_STREAM               DMA1_Stream4
-
-// Definition for SPId's NVIC
-#define I2Sx_IRQn                        SPI2_IRQn
-#define I2Sx_IRQHandler                  SPI2_IRQHandler
-#define I2Sx_DMA_TX_IRQn                 DMA1_Stream4_IRQn
-#define I2Sx_DMA_TX_IRQHandler           DMA1_Stream4_IRQHandler
-
-#define I2Sx_IRQPriority             DAC_IRQPriority
-#define I2Sx_IRQSubPriority          2
-#define I2Sx_DMA_TX_IRQPriority      DAC_IRQPriority
-#define I2Sx_DMA_TX_IRQSubPriority   1
-
-// dac8565 defines
-#define DAC8565_SET_ONE        ((uint8_t)0b00010000)
-#define DAC8565_PREP_ONE       ((uint8_t)0x0)
-#define DAC8565_SET_AND_UPDATE ((uint8_t)0b00100000)
-#define DAC8565_SET_ALL        ((uint8_t)0b00110100)
-#define DAC8565_REFRESH_ALL    ((uint8_t)0b00110000)
-
-void DAC_Init( uint16_t bsize, uint8_t chan_count );
-void DAC_Start(void);
-
-void DAC_CalibrateScalar( uint8_t channel, float scale );
-void DAC_CalibrateOffset( uint8_t channel, float volts );
-void DAC_PickleBlock( uint32_t* dac_pickle_ptr
-                    , float*    unpickled_data
-                    , uint16_t  bsize
-                    );
-
-void I2Sx_DMA_TX_IRQHandler(void);
-void I2Sx_IRQHandler(void);
-
-void HAL_I2S_TxCpltCallback( I2S_HandleTypeDef *hi2s );
-void HAL_I2S_TxHalfCpltCallback( I2S_HandleTypeDef *hi2s );
-void HAL_I2S_ErrorCallback( I2S_HandleTypeDef *hi2s );
-
-void DAC_I2S_MspInit(I2S_HandleTypeDef *hi2s);
-void DAC_I2S_MspDeInit(I2S_HandleTypeDef *hi2s);
-
-*/
diff --git a/ll/system.c b/ll/system.c
index 2e590ad..da7fe33 100644
--- a/ll/system.c
+++ b/ll/system.c
@@ -106,9 +106,9 @@ static void MPU_Config(void)
     // Configure the MPU attributes as WT for SRAM
     mpu.Enable           = MPU_REGION_ENABLE;
     // mpu.Enable           = MPU_REGION_DISABLE;
-    // mpu.BaseAddress      = 0x20020000;
-    mpu.BaseAddress      = 0x20000000;
-    mpu.Size             = MPU_REGION_SIZE_512KB;
+    mpu.BaseAddress      = 0x20020000;
+    // mpu.BaseAddress      = 0x20000000;
+    mpu.Size             = MPU_REGION_SIZE_256KB;
     mpu.AccessPermission = MPU_REGION_FULL_ACCESS;
     mpu.IsBufferable     = MPU_ACCESS_NOT_BUFFERABLE;
     mpu.IsCacheable      = MPU_ACCESS_CACHEABLE;
diff --git a/main.c b/main.c
index b52099e..92044c8 100755
--- a/main.c
+++ b/main.c
@@ -41,8 +41,8 @@ int main(void)
 
     // Drivers
     int max_timers = Timer_Init();
-    // IO_Init( max_timers-2 ); // use second-last timer
-    // IO_Start(); // must start IO before running lua init() script
+    IO_Init( max_timers-2 ); // use second-last timer
+    IO_Start(); // must start IO before running lua init() script
     events_init();
     Metro_Init( max_timers-2 ); // reserve 2 timers for USB & ADC
     clock_init( 100 ); // TODO how to pass it the timer?
diff --git a/stm32_flash.ld b/stm32_flash.ld
index 20465f2..a4cc30e 100755
--- a/stm32_flash.ld
+++ b/stm32_flash.ld
@@ -34,7 +34,7 @@ ENTRY(Reset_Handler)
 _estack = 0x20080000;    /* end of 512K RAM */
 
 /* Generate a link error if heap and stack don't fit into RAM */
-_Min_Heap_Size = 0x200;      /* required amount of heap  */
+_Min_Heap_Size = 0x1000;      /* required amount of heap  */
 _Min_Stack_Size = 0x10000; /* required amount of stack */
 
 /* Specify the memory areas */
diff --git a/usbd/usbd_main.c b/usbd/usbd_main.c
index fc73781..f018a7b 100755
--- a/usbd/usbd_main.c
+++ b/usbd/usbd_main.c
@@ -43,9 +43,9 @@ void OTG_HS_IRQHandler(void)
     HAL_PCD_IRQHandler(&hpcd);
 }
 
-extern TIM_HandleTypeDef USBTimHandle;
+// extern TIM_HandleTypeDef USBTimHandle;
 
-void TIMu_IRQHandler(void)
-{
-    HAL_TIM_IRQHandler(&USBTimHandle);
-}
+// void TIMu_IRQHandler(void)
+// {
+//     HAL_TIM_IRQHandler(&USBTimHandle);
+// }