oa_ex3_unityGainBuffer.c

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//*****************************************************************************
//  MSP430FG662x Demo - OA0, Unity-Gain Buffer Mode
//
//  Description: Configure OA0 for rail-to-rail input mode. The "+" terminal is
//  connected to OA0IP0 and the "-" terminal is connected to OA0IN0.
//  ACLK = n/a, MCLK = SMCLK = default DCO
//
//                MSP430FG662x
//             -------------------
//         /|\|                XIN|-
//          | |                   |
//          --|RST            XOUT|-
//            |                   |
//     "-" -->|P6.5/OA0IN0        |
//     "+" -->|P6.2/OA0IP0        |
//            |                   |
//            |          P6.4/OA0O|--> OA0 Output
//            |                   |
//
//*****************************************************************************
#include <driverlib.h>
 
int main(void)
{
  // Stop watchdog timer
  WDT_A_hold(WDT_A_BASE);
 
  // Select P6.2,5 OA0IP/N0 function
  GPIO_setAsPeripheralModuleFunctionOutputPin(
                GPIO_PORT_P6,
                GPIO_PIN2 + GPIO_PIN5
                );
 
  // Select OA0IP0 as "+" input
  // Select OA0IN0 as "-" input
  OA_closeSwitch(OA_0_BASE,
          OA_POSITIVE_INPUT_TERMINAL_SWITCH0,
          OA_NEGATIVE_INPUT_TERMINAL_SWITCH0,
          OA_GROUND_NONE
          );
 
  // Select rail-to-rail input mode
  OA_enableRailToRailInput(OA_0_BASE);
 
  // Wait for rail-to-rail input to be ready
  while (OA_INPUT_READY == OA_getRailToRailInputReadyStatus(OA_0_BASE));
 
  // Enable OA0 amplifier
  OA_enableAmplifierMode(OA_0_BASE);
 
  // LPM3
  LPM3;
 
  // Required only for debugger
  _NOP();
}