text: //###########################################################################
  //
  // FILE:   adc.c
  //
  // TITLE:  C28x ADC driver.
  //
  //###########################################################################
  // $TI Release: F2838x Support Library v3.03.00.00 $
  // $Release Date: Sun Oct  4 16:00:36 IST 2020 $
  // $Copyright:
  // Copyright (C) 2020 Texas Instruments Incorporated - http://www.ti.com/
  //
  // Redistribution and use in source and binary forms, with or without 
  // modification, are permitted provided that the following conditions 
  // are met:
  // 
  //   Redistributions of source code must retain the above copyright 
  //   notice, this list of conditions and the following disclaimer.
  // 
  //   Redistributions in binary form must reproduce the above copyright
  //   notice, this list of conditions and the following disclaimer in the 
  //   documentation and/or other materials provided with the   
  //   distribution.
  // 
  //   Neither the name of Texas Instruments Incorporated nor the names of
  //   its contributors may be used to endorse or promote products derived
  //   from this software without specific prior written permission.
  // 
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
  // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
  // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 
  // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
  // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 
  // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 
  // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 
  // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  // $
  //###########################################################################
  
  #include "adc.h"
  
  //
  // The following macro calculates the INL trim location in OTP memory
  // required to calibrate the ADC linearity.  Use this in the
  // ADC_setMode() function only.
  //
  #define ADC_getINLTrimOTPLoc(offset) ((uint32_t *)(0x70128U + (0xC * offset)))
  
  //
  // This macro calculates the ADC offset trim location in OTP memory required
  // to calibrate ADC offset. Use this in the ADC_setMode() function only.
  //
  #define ADC_getOffsetTrimOTPLoc(offset)     ((uint16_t *)(0x70158U + offset))
  
  //
  // TI-OTP key value expected to be programmed in trimmed device
  //
  #define TI_OTP_DEV_KEY                          (0x5A5AU)
  
  //
  // Macro to read the key value programmed in the device
  //
  #define TI_OTP_DEV_PRG_KEY                      (HWREGH(0x70238UL))
  
  //*****************************************************************************
  //
  // ADC_setMode
  //
  //*****************************************************************************
  void
  ADC_setMode(uint32_t base, ADC_Resolution resolution,
              ADC_SignalMode signalMode)
  {
      uint16_t offsetIndex = 0U, offsetTrim = 0U, i;
      uint32_t * inlTrimAddress;
  
      //
      // Check the arguments.
      //
      ASSERT(ADC_isBaseValid(base));
  
      //
      // Check for correct signal mode & resolution. In this device:
      // Differential signal conversions are supported in 16-bit only
      //
      if(signalMode == ADC_MODE_DIFFERENTIAL)
      {
          ASSERT(resolution == ADC_RESOLUTION_16BIT);
      }
  
      EALLOW;
      switch(base)
      {
          case ADCA_BASE:
              offsetIndex = (uint16_t)(0U);
              inlTrimAddress = ADC_getINLTrimOTPLoc(0U);
              break;
          case ADCB_BASE:
              offsetIndex = (uint16_t)(1U);
              inlTrimAddress = ADC_getINLTrimOTPLoc(1U);
              break;
          case ADCC_BASE:
              offsetIndex = (uint16_t)(2U);
              inlTrimAddress = ADC_getINLTrimOTPLoc(2U);
              break;
          case ADCD_BASE:
              offsetIndex = (uint16_t)(3U);
              inlTrimAddress = ADC_getINLTrimOTPLoc(3U);
              break;
          default:
              //
              // Invalid base address!
              //
              offsetIndex = (uint16_t)(0U);
              inlTrimAddress = ADC_getINLTrimOTPLoc(0U);
              break;
      }
  
      //
      // Get the offset trim value programmed into OTP
      //
      offsetIndex += (4U * ((resolution == ADC_RESOLUTION_16BIT) ? 1U : 0U));
  
      if(TI_OTP_DEV_PRG_KEY == TI_OTP_DEV_KEY)
      {
          offsetTrim = (*(uint16_t *)(ADC_getOffsetTrimOTPLoc(offsetIndex)));
          offsetTrim = (signalMode == ADC_MODE_SINGLE_ENDED) ?
                                         (offsetTrim >> 8):(offsetTrim & 0xFF);
      }
      else
      {
          offsetTrim = 0U;
      }
  
      //
      // Also apply the offset trim and, if needed, linearity trim correction.
      // Offset Trim is not updated here in case of untrimmed devices.
      //
      if(offsetTrim > 0x0U)
      {
          HWREGH(base + ADC_O_OFFTRIM) = offsetTrim;
      }
  
      //
      // Update INL trim values to ADC trim registers
      //
      if(TI_OTP_DEV_PRG_KEY == TI_OTP_DEV_KEY)
      {
          for(i = 0U; i < 6U; i++)
          {
              HWREG(base + ADC_O_INLTRIM1 + (i * 2)) = (*inlTrimAddress++);
          }
      }
  
      if(resolution == ADC_RESOLUTION_12BIT)
      {
          //
          // 12-bit linearity trim workaround
          //
          HWREG(base + ADC_O_INLTRIM1) &= 0xFFFF0000U;
          HWREG(base + ADC_O_INLTRIM2) &= 0xFFFF0000U;
          HWREG(base + ADC_O_INLTRIM4) &= 0xFFFF0000U;
          HWREG(base + ADC_O_INLTRIM5) &= 0xFFFF0000U;
      }
  
      //
      // Apply the resolution and signalMode to the specified ADC.
      //
      HWREGH(base + ADC_O_CTL2) = (HWREGH(base + ADC_O_CTL2) &
                                   ~(ADC_CTL2_RESOLUTION | ADC_CTL2_SIGNALMODE)) |
                                  ((uint16_t)resolution | (uint16_t)signalMode);
      EDIS;
  }
  //*****************************************************************************
  //
  // ADC_setPPBTripLimits
  //
  //*****************************************************************************
  void
  ADC_setPPBTripLimits(uint32_t base, ADC_PPBNumber ppbNumber,
                       int32_t tripHiLimit, int32_t tripLoLimit)
  {
      uint32_t ppbHiOffset;
      uint32_t ppbLoOffset;
  
      //
      // Check the arguments.
      //
      ASSERT(ADC_isBaseValid(base));
      ASSERT((tripHiLimit <= 65535) && (tripHiLimit >= -65536));
      ASSERT((tripLoLimit <= 65535) && (tripLoLimit >= -65536));
  
      //
      // Get the offset to the appropriate trip limit registers.
      //
      ppbHiOffset = (ADC_PPBxTRIPHI_STEP * (uint32_t)ppbNumber) +
                    ADC_O_PPB1TRIPHI;
      ppbLoOffset = (ADC_PPBxTRIPLO_STEP * (uint32_t)ppbNumber) +
                    ADC_O_PPB1TRIPLO;
  
      EALLOW;
  
      //
      // Set the trip high limit.
      //
      HWREG(base + ppbHiOffset) =
          (HWREG(base + ppbHiOffset) & ~ADC_PPBTRIP_MASK) |
          ((uint32_t)tripHiLimit & ADC_PPBTRIP_MASK);
  
      //
      // Set the trip low limit.
      //
      HWREG(base + ppbLoOffset) =
          (HWREG(base + ppbLoOffset) & ~ADC_PPBTRIP_MASK) |
          ((uint32_t)tripLoLimit & ADC_PPBTRIP_MASK);
  
      EDIS;
  }
  