ADS122U04EVM: Possible to communicate via COM-Port

Thanks for the helpful answer Bob,

my endgoal is to use an excelsheet to collect and show the data results. The Registers should be set by an included table. The enddata should be printed an additional table. For that purpose i want to use an makro that uses the win-api to get a communcation to the serial port. Thats an example for 20SPS, so i use a sleep time of 50ms in the continous-conversation between each data i would receive.

Here is a short summary what the makro-module does:

- getting data of the excel table: settings for each register (saving in a value of 1 Byte for each), getting the number of samples to receive,

-initialize the communication to the serial port (port id, baudrate, paritiy, number of databits, stopbit)

-sending snychro and resetcommand (&h55,&h06) then sleep 50ms

-loop for 0 to 4: sending synchro an registersettings commands with &h55, &h40,&h03 for example, next iteration: &h55,&h41,&h02 and so on (the register setting are only for example like in the first &h03)

-setting ads122u04 in continous-conversation-mode by sending &h55, &h08

-now loop with the number of samples that should be collected:

-checking DRDY in register 3 to control if new data is available by sending &h55, &h22

-if data isn't available try again uo to 10 times

-if data available send &h55, &h10

-receive data and put it into a variables (3Bytes)

-sleep 50ms

-print data in to a cell in the table

-next iteration, up to the iteration number that is the same as the sample number to collect

shutting down the ads122u04 with &h55, &h02 ; then closing the serial connection

If i understand you right, then that should be possible by using for example an usb to serial adapter that includes an TTL-Uart (for example with an ft232bl). Then i have to remove the connection on the ads122u04evm that lets the tiva microchip and the ads122u04 communicate. So it should now be possible to connect the RX,TX pins from the adapter to the TX,RX marks on the EVM? In theory would it work this way?

Thanks a lot, greets Jan

Hi Bob,

sorry for the late reply, was ver busy the last time, but thanks for your intention to help me.

I've found a msp430fr5994evm in my collection, so i've tried to use it for a extern communication as an uart. As you explained I installed a jumper to set the Tiva chip into reset state. Then I connected the uart-pins of the msp430fr5994evm to the j3 pins on the ads122u04evm (rx to tx, tx to rx). For the msp430fr5994 i use a programm in which i've defined two uarts. The code is posted below. UCA0 is used as a software uart, so i use a terminal program connected to the port4 to transmitt data to the msp430fr5994. this data is transmitted to the second uart, which is used as the connection between the msp430fr5994evm and the ads122u04evm.

But sadly thats doesn't solve my probelm, i doesn't get any data transfered by the ads122u04. Perhaps you can help me again.

Thanks and greets Jan Dombrowski

#include <msp430.h>
unsigned char data1;

int main(void)
{
    WDTCTL = WDTPW | WDTHOLD;               // Stop Watchdog


    // Configure GPIO
    P6SEL1 &= ~(BIT0 | BIT1);
    P6SEL0 |= (BIT0 | BIT1);                // USCI_A3 UART operation

    P2SEL0 &= ~(BIT0 | BIT1);               //usci0
    P2SEL1 |= BIT0 | BIT1;

    // Disable the GPIO power-on default high-impedance mode to activate
    // previously configured port settings
    PM5CTL0 &= ~LOCKLPM5;

    // Startup clock system with max DCO setting ~8MHz
    CSCTL0_H = CSKEY_H;                     // Unlock CS registers
    CSCTL1 = DCOFSEL_3 | DCORSEL;           // Set DCO to 8MHz
    CSCTL2 = SELA__VLOCLK | SELS__DCOCLK | SELM__DCOCLK;
    CSCTL3 = DIVA__1 | DIVS__1 | DIVM__1;   // Set all dividers
    CSCTL0_H = 0;                           // Lock CS registers

    // Configure USCI_A3 for UART mode
    UCA3CTLW0 = UCSWRST;                    // Put eUSCI in reset
    UCA0CTLW0 = UCSWRST;
    UCA3CTLW0 |= UCSSEL__SMCLK;             // CLK = SMCLK
    UCA0CTLW0 |= UCSSEL__SMCLK;

    // Baud Rate calculation
    // 8000000/(16*9600) = 52.083
    // Fractional portion = 0.083
    // User's Guide Table 21-4: UCBRSx = 0x04
    // UCBRFx = int ( (52.083-52)*16) = 1
    UCA3BRW = 52;     // 8000000/16/9600
    UCA0BRW = 52;
    UCA3MCTLW |= UCOS16 | UCBRF_1 | 0x4900;
    UCA0MCTLW |= UCOS16 | UCBRF_1 | 0x4900;
    UCA3CTLW0 &= ~UCSWRST;                  // Initialize eUSCI
    UCA0CTLW0 &= ~UCSWRST;
    UCA3IE |= UCRXIE;                       // Enable USCI_A3 RX interrupt
    UCA0IE |= UCRXIE;

    __bis_SR_register(LPM3_bits | GIE);     // Enter LPM3, interrupts enabled
    __no_operation();                       // For debugger
}

#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector=EUSCI_A3_VECTOR
__interrupt void USCI_A3_ISR(void)
#elif defined(__GNUC__)
void __attribute__ ((interrupt(EUSCI_A3_VECTOR))) USCI_A3_ISR (void)
#else
#error Compiler not supported!
#endif
{
    switch(__even_in_range(UCA3IV, USCI_UART_UCTXCPTIFG))
    {
        case USCI_NONE: break;
        case USCI_UART_UCRXIFG:
            while(!(UCA3IFG&UCTXIFG));
            UCA0TXBUF = UCA3RXBUF;
            __no_operation();
            break;
        case USCI_UART_UCTXIFG: break;
        case USCI_UART_UCSTTIFG: break;
        case USCI_UART_UCTXCPTIFG: break;
        default: break;
    }
}

#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector=EUSCI_A0_VECTOR
__interrupt void USCI_A0_ISR(void)
#elif defined(__GNUC__)
void __attribute__ ((interrupt(EUSCI_A0_VECTOR))) USCI_A0_ISR (void)
#else
#error Compiler not supported!
#endif
{
    switch(__even_in_range(UCA0IV, USCI_UART_UCTXCPTIFG))
    {
        case USCI_NONE: break;
        case USCI_UART_UCRXIFG:
            while(!(UCA0IFG&UCTXIFG));
            UCA3TXBUF = UCA0RXBUF;
            __no_operation();
            break;
        case USCI_UART_UCTXIFG: break;
        case USCI_UART_UCSTTIFG: break;
        case USCI_UART_UCTXCPTIFG: break;
        default: break;
    }
}

Hey Bob,

i've taken a pciture of the situation the usb-cables are connected to my pc. Ifi try to get an conversation in this state, i receive no answer from ads. If i remove the jumpercable at jp1, it is working.