Tinkering TI MSP430F5529

ADC12 Sampling Multiple Input

Till now, we have seen only one ADC channel in action. We have seen examples of single internal and external channels only. However, in real-life and in many occasions, we may need the use of more than one ADC channel. For example, we will need multiple ADC channels when crafting an Uninterrupted Power Supply (UPS). In an UPS, we will be needing to measure battery voltage, battery charging and discharging current, AC output voltage and current, internal temperature and so on. In such cases, multiple ADC channels are musts. This example demonstrates how to use multiple ADC channels of a MSP430F5529 microcontroller. 

Code Example

#include "driverlib.h"
#include "delay.h"
#include "lcd.h"
#include "lcd_print.h"

unsigned long res[2] = {0, 0};

void clock_init(void);
void GPIO_init(void);
void ADC12_init(void);

#pragma vector = ADC12_VECTOR
__interrupt void ADC12ISR (void)
{
    switch (__even_in_range(ADC12IV, 34))
    {
        case  0: break;   //Vector  0:  No interrupt
        case  2: break;   //Vector  2:  ADC overflow
        case  4: break;   //Vector  4:  ADC timing overflow
        case  6: break;   
  {
		res[0] = ADC12_A_getResults(ADC12_A_BASE,
                                        ADC12_A_MEMORY_0);
            break;
  }		 	 //Vector  6:  ADC12IFG0
        case  8:
        {
            res[1] = ADC12_A_getResults(ADC12_A_BASE,
                                        ADC12_A_MEMORY_1);
            break;
        }                 //Vector  8:  ADC12IFG1
        case 10: break;   //Vector 10:  ADC12IFG2
        case 12: break;   //Vector 12:  ADC12IFG3
        case 14: break;   //Vector 14:  ADC12IFG4
        case 16: break;   //Vector 16:  ADC12IFG5
        case 18: break;   //Vector 18:  ADC12IFG6
        case 20: break;   //Vector 20:  ADC12IFG7
        case 22: break;   //Vector 22:  ADC12IFG8
        case 24: break;   //Vector 24:  ADC12IFG9
        case 26: break;   //Vector 26:  ADC12IFG10
        case 28: break;   //Vector 28:  ADC12IFG11
        case 30: break;   //Vector 30:  ADC12IFG12
        case 32: break;   //Vector 32:  ADC12IFG13
        case 34: break;   //Vector 34:  ADC12IFG14
        default: break;
    }
}

void main(void)
{
    WDT_A_hold(WDT_A_BASE);

    clock_init();
    GPIO_init();
    ADC12_init();

    LCD_init();
    LCD_clear_home();

    LCD_goto(0, 0);
    LCD_putstr("CH0:");

    LCD_goto(0, 1);
    LCD_putstr("CH1:");

    while(1)
    {

        print_I(11, 0, res[0]);
        print_I(11, 1, res[1]);
        delay_ms(100);
    };
}

void clock_init(void)
{
    PMM_setVCore(PMM_CORE_LEVEL_3);

    GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P5,
                                               (GPIO_PIN4 | GPIO_PIN2));

    GPIO_setAsPeripheralModuleFunctionOutputPin(GPIO_PORT_P5,
                                                (GPIO_PIN5 | GPIO_PIN3));

    UCS_setExternalClockSource(XT1_FREQ,
                               XT2_FREQ);

    UCS_turnOnXT2(UCS_XT2_DRIVE_4MHZ_8MHZ);

    UCS_turnOnLFXT1(UCS_XT1_DRIVE_0,
                    UCS_XCAP_3);

    UCS_initClockSignal(UCS_FLLREF,
                        UCS_XT2CLK_SELECT,
                        UCS_CLOCK_DIVIDER_4);

    UCS_initFLLSettle(MCLK_KHZ,
                      MCLK_FLLREF_RATIO);

    UCS_initClockSignal(UCS_SMCLK,
                        UCS_XT2CLK_SELECT,
                        UCS_CLOCK_DIVIDER_2);

    UCS_initClockSignal(UCS_ACLK,
                        UCS_XT1CLK_SELECT,
                        UCS_CLOCK_DIVIDER_1);
}

void GPIO_init(void)
{
    GPIO_setAsOutputPin(GPIO_PORT_P4,
                        GPIO_PIN7);

    GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P6,
                                               (GPIO_PIN0 | GPIO_PIN1));
}

void ADC12_init(void)
{
    ADC12_A_configureMemoryParam CH0_configureMemoryParam = {0};
    ADC12_A_configureMemoryParam CH1_configureMemoryParam = {0};

    CH0_configureMemoryParam.memoryBufferControlIndex = ADC12_A_MEMORY_0;
    CH0_configureMemoryParam.inputSourceSelect = ADC12_A_INPUT_A0;
    CH0_configureMemoryParam.positiveRefVoltageSourceSelect = ADC12_A_VREFPOS_AVCC;
    CH0_configureMemoryParam.negativeRefVoltageSourceSelect = ADC12_A_VREFNEG_AVSS;
    CH0_configureMemoryParam.endOfSequence = ADC12_A_NOTENDOFSEQUENCE;

    CH1_configureMemoryParam.memoryBufferControlIndex = ADC12_A_MEMORY_1;
    CH1_configureMemoryParam.inputSourceSelect = ADC12_A_INPUT_A1;
    CH1_configureMemoryParam.positiveRefVoltageSourceSelect = ADC12_A_VREFPOS_AVCC;
    CH1_configureMemoryParam.negativeRefVoltageSourceSelect = ADC12_A_VREFNEG_AVSS;
    CH1_configureMemoryParam.endOfSequence = ADC12_A_ENDOFSEQUENCE;

    ADC12_A_init(ADC12_A_BASE,
                 ADC12_A_SAMPLEHOLDSOURCE_SC,
                 ADC12_A_CLOCKSOURCE_ACLK,
                 ADC12_A_CLOCKDIVIDER_1);

    ADC12_A_setupSamplingTimer(ADC12_A_BASE,
                               ADC12_A_CYCLEHOLD_256_CYCLES,
                               ADC12_A_CYCLEHOLD_4_CYCLES,
                               ADC12_A_MULTIPLESAMPLESENABLE);

    ADC12_A_setResolution(ADC12_A_BASE,
                          ADC12_A_RESOLUTION_12BIT);

    ADC12_A_configureMemory(ADC12_A_BASE,
                            &CH0_configureMemoryParam);

    ADC12_A_configureMemory(ADC12_A_BASE,
                            &CH1_configureMemoryParam);

    ADC12_A_clearInterrupt(ADC12_A_BASE,
                           ADC12IFG0);

    ADC12_A_enableInterrupt(ADC12_A_BASE,
                            ADC12IE0);	

    ADC12_A_clearInterrupt(ADC12_A_BASE,
                           ADC12IFG1);

    ADC12_A_enableInterrupt(ADC12_A_BASE,
                            ADC12IE1);

    __enable_interrupt();

    ADC12_A_enable(ADC12_A_BASE);

    ADC12_A_startConversion(ADC12_A_BASE,
                            ADC12_A_MEMORY_0,
                            ADC12_A_REPEATED_SEQOFCHANNELS);
}

Hardware Setup

Explanation

ADC12’s settings have two sections. One is common and the other is channel dependent.

Common settings include ADC’s clock setup, resolution and sample-hold timer settings. These will be applicable for all channels.

ADC12_A_init(ADC12_A_BASE,
             ADC12_A_SAMPLEHOLDSOURCE_SC,
             ADC12_A_CLOCKSOURCE_ACLK,
             ADC12_A_CLOCKDIVIDER_1);

ADC12_A_setupSamplingTimer(ADC12_A_BASE,
                           ADC12_A_CYCLEHOLD_256_CYCLES,
                           ADC12_A_CYCLEHOLD_4_CYCLES,
                           ADC12_A_MULTIPLESAMPLESENABLE);

ADC12_A_setResolution(ADC12_A_BASE, ADC12_A_RESOLUTION_12BIT);

Channel parameters define ADC memory location, references and sequence info. Additionally, if interrupts are used, they need to applied separately.

CH0_configureMemoryParam.memoryBufferControlIndex = ADC12_A_MEMORY_0;
CH0_configureMemoryParam.inputSourceSelect = ADC12_A_INPUT_A0;
CH0_configureMemoryParam.positiveRefVoltageSourceSelect = ADC12_A_VREFPOS_AVCC;
CH0_configureMemoryParam.negativeRefVoltageSourceSelect = ADC12_A_VREFNEG_AVSS;
CH0_configureMemoryParam.endOfSequence = ADC12_A_NOTENDOFSEQUENCE;

CH1_configureMemoryParam.memoryBufferControlIndex = ADC12_A_MEMORY_1;
CH1_configureMemoryParam.inputSourceSelect = ADC12_A_INPUT_A1;
CH1_configureMemoryParam.positiveRefVoltageSourceSelect = ADC12_A_VREFPOS_AVCC;
CH1_configureMemoryParam.negativeRefVoltageSourceSelect = ADC12_A_VREFNEG_AVSS;
CH1_configureMemoryParam.endOfSequence = ADC12_A_ENDOFSEQUENCE;

....

ADC12_A_clearInterrupt(ADC12_A_BASE, ADC12IFG0);
ADC12_A_enableInterrupt(ADC12_A_BASE, ADC12IE0);

ADC12_A_configureMemory(ADC12_A_BASE, &CH0_configureMemoryParam);
	
ADC12_A_clearInterrupt(ADC12_A_BASE, ADC12IFG1);
ADC12_A_enableInterrupt(ADC12_A_BASE, ADC12IE1);

ADC12_A_configureMemory(ADC12_A_BASE, &CH1_configureMemoryParam);

At this point, I would like to highlight the concept of sequence. When multiple ADC channels are used, ADC conversions are done sequentially, i.e. one after another. In our code, we have to specify one channel as the end of sequence while denoting other channels as no end of sequence. In this way, channels are systematically queued.

ADC reading process is same as the one we saw in the ADC interrupt example. The only exception is the usage of two vectors as two channels are in different memory planes.

#pragma vector = ADC12_VECTOR
__interrupt void ADC12ISR (void)
{
    switch (__even_in_range(ADC12IV, 34))
    {
        case  0: break;   //Vector  0:  No interrupt
        case  2: break;   //Vector  2:  ADC overflow
        case  4: break;   //Vector  4:  ADC timing overflow
        case  6: break;   
  {
		res[0] = ADC12_A_getResults(ADC12_A_BASE,
                                        ADC12_A_MEMORY_0);
            break;
  }		 	 //Vector  6:  ADC12IFG0
        case  8:
        {
            res[1] = ADC12_A_getResults(ADC12_A_BASE,
                                        ADC12_A_MEMORY_1);
            break;
        }                 //Vector  8:  ADC12IFG1
        case 10: break;   //Vector 10:  ADC12IFG2
        case 12: break;   //Vector 12:  ADC12IFG3
        case 14: break;   //Vector 14:  ADC12IFG4
        case 16: break;   //Vector 16:  ADC12IFG5
        case 18: break;   //Vector 18:  ADC12IFG6
        case 20: break;   //Vector 20:  ADC12IFG7
        case 22: break;   //Vector 22:  ADC12IFG8
        case 24: break;   //Vector 24:  ADC12IFG9
        case 26: break;   //Vector 26:  ADC12IFG10
        case 28: break;   //Vector 28:  ADC12IFG11
        case 30: break;   //Vector 30:  ADC12IFG12
        case 32: break;   //Vector 32:  ADC12IFG13
        case 34: break;   //Vector 34:  ADC12IFG14
        default: break;
    }
}

Demo

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24 comments

  • Hi,
    Im interfacing MSP430F5529 with MAX17055 fuel guage. while reading 16 bit value, the first byte im receiving is 0. so while reading multiple registers continuously the data exchange is happening, but im getting the correct data. Can anyone suggest me what will be the issue? why im getting 0 in first byte?

    read16_bit data code:

    uint16_t value = 0;
    USCI_B_I2C_setslaveaddress(USCI_B1_BASE, slave_address);
    USCI_B_I2C_setmode(USCI_B1_BASE, USCI_B_I2C_TRANSMIT_MODE);
    USCI_B_I2C_masterSendStart(USCI_B1_BASE);
    while (!USCI_B_I2C_masterSendStart(USCI_B1_BASE));

    USCI_B_I2C_mastterSendSingleByte(USCI_B1_BASE, reg_address);

    USCI_B_I2C_setslaveaddress(USCI_B1_BASE, slave_address);
    USCI_B_I2C_setmode(USCI_B1_BASE, USCI_B_I2C_TRANSMIT_MODE);
    USCI_B_I2C_masterReceiveMultiByteStart(USCI_B1_BASE);

    uint8_t lb = USCI_B_I2C_masterReceiveMultiByteNext(USCI_B1_BASE);
    uint8_t hb = USCI_B_I2C_masterReceiveMultiByteFinish(USCI_B1_BASE);

    while (USCI_B_I2C_isBusBusy(USCI_B_BASE));

    value = lb << 8;
    value |= hb;
    return value;

  • Hi, im trying to send the command from the terminal view. i can able to send the command and tried to blink p1.0 led in msp430f5529 controller, its working fine. And im using led driver IS31FL3236A interfaced with msp430f5529 controller, i can able to interface im getting the expected output.

    now i need to send the command from seriak monitor based on that command i2c communication need to start. both communication are working fine, when it runs separately. its not working when i tried to combine.

    any one had any idea, why it is happening or what will be the issue?

    • It could be due to:

      1. conflicts in clock settings
      2. hardware conflict like pin mapping
      3. code is getting stuck or waiting for one communication line to finish
      4. use of polling method instead of interrupt-driven coding

      • Hi, thank you for the respose.
        Do I need to use different clock initialization for I2C and UART communication? if YES, can you explain how to do that?

      • Is there any example on how to implement polling method in uart?

        • Why go for polling method when it is a blocking method of coding? It is better to use interrupts instead at least for UART receive.

          • yes!! currently in my code, only for uart im using interrupts to recieve command from serial monitor. Im not using interrupt for I2C communication.

          • so the issue is must be in clock initialization. right?

            For UART, im using USCI_A1_BASE. and for I2C, im using USCI_B1_BASE.

            And another thing i need to ask is, in uart when i tried blink led(p1.0) in msp430f5529 by passing command. here, without clock I’m getting output. how it is possible?

            And for both i2c and uart i gave SMCLK with 1Mhz

  • I am surprised and happy to find this tutorial on the F5529 as TI makes a lot of different devices.
    Thank you very much for putting in the extra knowledge in each segment, made reading worthwhile.
    Good Work!

  • lovely tutorial but to be honest I don’t think I’d be investing my time on this board to start with it’s not cheap and readily available as the stm32 boards can you please do more tutorials on stm32 board’s and the stc micros thanks

  • Hello, I try to program MSP430FR6047 but i get error “the debug interface to the device has been secured”. when flashing using uniflash and when program using CCS this happen. can you help me to solve this problem

  • Pingback: Tinkering TI MSP430F5529 – gStore

  • Hello
    I am doing project of msp430g2553 interface(using i2c communication) with temp 100(temperature sensor) and try to read the temperature in dispaly(16*2) but didn’t get the out put (using code composer studio) can u share me any example code for this project

    Thank you sir,

  • Where is lcd_print.h?

  • You want the truth? TI makes and sell “underpowered micros”, you know? Low everything, not only the power but also peripherals. So the price is not justified.

    Otherwise, if I’ll move there, I’ll introduce them to my small hobby projects – there are still some advantages.

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