/*******************************************************************************
* File Name: main.c
*
* Version: 2.00
*
* Description:
* This example project shows how to sample four different channels using
* SAR MUX and ADC, and send channel output to HyperTerminal (PC) using UART.
*
********************************************************************************
* Copyright 2013-2018, Cypress Semiconductor Corporation. All rights reserved.
* This software is owned by Cypress Semiconductor Corporation and is protected
* by and subject to worldwide patent and copyright laws and treaties.
* Therefore, you may use this software only as provided in the license agreement
* accompanying the software package from which you obtained this software.
* CYPRESS AND ITS SUPPLIERS MAKE NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
* WITH REGARD TO THIS SOFTWARE, INCLUDING, BUT NOT LIMITED TO, NONINFRINGEMENT,
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*******************************************************************************/
#include <project.h>
/* Macro definitions */
#define LOW (0u)
#define HIGH (1u)
#define CHANNEL_1 (0u)
#define CHANNEL_2 (1u)
#define CHANNEL_3 (2u)
#define CHANNEL_4 (3u)
#define NO_OF_CHANNELS (4u)
#define CLEAR_SCREEN (0x0C)
#define CONVERT_TO_ASCII (0x30u)
/* Resistor Values and Gain */
#define RG (2200u)
#define R1 (10000u)
#define GAIN (1 + 2 * (float)R1 / RG)
/* Send the channel number and voltage to UART */
static void SendChannelVoltage(uint8 channel, int16 mVolts);
/* Interrupt prototypes */
CY_ISR_PROTO(ADC_ISR_Handler);
/* Global variables */
volatile uint32 windowFlag = 0u;
volatile uint8 dataReady = 0u;
volatile uint8 channelFlag = 0u;
/*******************************************************************************
* Function Name: main
********************************************************************************
*
* Summary:
* Performs the following tasks:
* - Start the components.
* - Starts ADC conversion.
* - Buffer ADC results.
* - Sends the result to HyperTerminal (PC) using UART.
* - Turns ON an LED when ADC input is outside the voltage
* window of 250mV to 750mV.
*
* Parameters:
* None.
*
* Return:
* None.
*
*******************************************************************************/
int main()
{
uint8 channel = CHANNEL_1;
int16 adcVal[4u];
int16 mVolts;
int16 previousValue = 0;
int32 adcGain;
/* Start the Components */
Opamp_1_Start();
Opamp_2_Start();
UART_Start();
ADC_Start();
/* Start ISRs */
ADC_IRQ_StartEx(ADC_ISR_Handler);
/* Enable global interrupts */
CyGlobalIntEnable;
/* Start ADC conversion */
ADC_StartConvert();
/* Calculate gain for the first channel */
adcGain = (((int32)ADC_SAR_WRK_MAX_12BIT * ADC_10MV_COUNTS) +
ADC_DEFAULT_VREF_MV_VALUE) / (ADC_DEFAULT_VREF_MV_VALUE * 2);
adcGain *= GAIN;
ADC_SetGain(CHANNEL_1, adcGain);
for(;;)
{
while(dataReady == 0u)
{
; /* Wait for ADC conversion */
}
/* Buffer the results */
adcVal[CHANNEL_1] = ADC_GetResult16(CHANNEL_1);
adcVal[CHANNEL_2] = ADC_GetResult16(CHANNEL_2);
adcVal[CHANNEL_3] = ADC_GetResult16(CHANNEL_3);
adcVal[CHANNEL_4] = ADC_GetResult16(CHANNEL_4);
/* Check for ADC window limit interrupt */
if(windowFlag != 0u)
{
/* Turn ON the LED when input is outside the voltage window (250mV - 750mV) */
LED_Write(LOW);
/* Note: If LED is active HIGH, then replace "LOW" with "HIGH" */
}
else
{
/* Turn OFF the LED when input is within the voltage window (250mV - 750mV) */
LED_Write(HIGH);
/* Note:If LED is active HIGH, then replace "HIGH" with "LOW" */
}
/* Switch processing */
if(SW2_Read() == 0u)
{
CyDelay(5u); /* Basic debounce delay */
if(SW2_Read() == 0u)
{
channelFlag = 1u;
/* Update the channel number */
channel++;
channel %= NO_OF_CHANNELS;
}
while(SW2_Read() == 0u)
{
; /* Wait till button released */
}
}
/* Convert the ADC counts of active channel to mVolts */
mVolts = ADC_CountsTo_mVolts(channel, adcVal[channel]);
/* If ADC result or channel has been changed, send the data to UART */
if((previousValue != mVolts) || (channelFlag != 0u))
{
SendChannelVoltage(channel, mVolts);
previousValue = mVolts;
/* Clear the flag */
channelFlag = 0u;
}
dataReady = 0u;
}
}
/*******************************************************************************
* Function Name: SendChannelVoltage
********************************************************************************
*
* Summary:
* Performs the following tasks:
* - Converts the channel number to ASCII character
* - Clears terminal screen
* - Sends the channel number and voltage to UART
*
* Parameters:
* uint8 channel : Channel Number
* int16 mVolts : ADC counts
*
* Return:
* None.
*
********************************************************************************/
static void SendChannelVoltage(uint8 channel, int16 mVolts)
{
/* Clear screen */
UART_UartPutChar(CLEAR_SCREEN);
UART_UartPutString("Channel ");
/* Display the channel number starting from 1 */
channel++;
channel += CONVERT_TO_ASCII;
UART_UartPutChar(channel);
UART_UartPutString(" = ");
/* Find the sign of the result */
if(mVolts < 0)
{
UART_UartPutString("-");
mVolts = -mVolts;
}
/* Send voltage to UART */
UART_UartPutChar((mVolts/1000u) + CONVERT_TO_ASCII);
mVolts %= 1000u;
UART_UartPutChar((mVolts/100u) + CONVERT_TO_ASCII);
mVolts %= 100u;
UART_UartPutChar((mVolts/10u) + CONVERT_TO_ASCII);
mVolts %= 10u;
UART_UartPutChar(mVolts + CONVERT_TO_ASCII);
UART_UartPutString(" mV");
UART_UartPutCRLF(0u);
}
/******************************************************************************
* Function Name: ADC_ISR_Handler
*******************************************************************************
*
* Summary:
* Interrupt Service Routine. Check the ADC status and sets window and data
* ready flags.
*
******************************************************************************/
CY_ISR(ADC_ISR_Handler)
{
uint32 intr_status;
/* Read interrupt status registers */
intr_status = ADC_SAR_INTR_MASKED_REG;
/* Check for End of Scan interrupt */
if((intr_status & ADC_EOS_MASK) != 0u)
{
/* Read range interrupt status and raise the flag */
windowFlag = ADC_SAR_RANGE_INTR_MASKED_REG;
/* Clear range detect status */
ADC_SAR_RANGE_INTR_REG = windowFlag;
dataReady = 1u;
}
/* Clear handled interrupt */
ADC_SAR_INTR_REG = intr_status;
}
/* [] END OF FILE */
