MSP430FR6989: Third UART

Vijay Kolaventy

I am using the following on Pins FR6989.

    // Init LFXT Pins
    PJSEL0 = BIT4 | BIT5;                   // PJ.4(LFXIN), PJ.5(LFXOUT)

    // Init UART_A0 Pins
    P4SEL0 |= BIT2 | BIT3;                  // Pins 4.2(TX) 4.3(RX)
    P4SEL1 &= ~(BIT2 | BIT3);                // USCI_A0 UART

    // Init UART_A1 Pins
    P3SEL0 |= BIT4 | BIT5;                  // Pins P3.4(TX) P3.5(RX)
    P3SEL1 &= ~(BIT4 | BIT5);               // USCI_A1 UART operation using Backchannel

     // Init I2C
    P4SEL1 |= BIT0 | BIT1;                  // I2C P4.0 (SDA) P4.1(SCL)

    // Set VeRef+ (External Reference) & VeRef- to AVSS
    P1SEL1 |= REF_PIN;                      // Configure P1.1 to External VeRef 2.048V
    P1SEL0 |= REF_PIN;

    // ADC Input with VeRef
    P8SEL0 |= 0xF0;                         // Set Pins A4-A7 for ADC
    P8SEL1 |= 0xF0;

    // Sensor Board Enable Pins
    P9SEL0 &= ~(MENB1 | MENB2 | MENB3 | MENB4);
    P9SEL1 &= ~(MENB1 | MENB2 | MENB3 | MENB4);
    P9DIR |= MENB1 | MENB2 | MENB3 | MENB4;
    P9OUT |= MENB1 | MENB2 | MENB3 | MENB4;

I need one more UART for sensor with RX485 output which will be connected through MAX485 module. As per datasheet, there are only 2 UARTS for MSPFR6989. Correct if I am wrong. I need at least 3 UARTS (4 UARTS is better), 1 I2C, 1 SPI. Please suggest Pin config. Is software UART possible?

Regards

Vijay

over 6 years ago

0 zrno soli over 6 years ago

Guru 34943 points

For what this 2 UARTS are used?

0 Vijay Kolaventy over 6 years ago in reply to zrno soli

Intellectual 870 points

I am using one uart for gprs, two for reading data from sensors. If possible I want to use one more for debug

0 zrno soli over 6 years ago in reply to Vijay Kolaventy

Guru 34943 points

Vijay Kolaventy said:

I am using one uart for gprs, two for reading data from sensors. If possible I want to use one more for debug

For debug can be used mailbox system (by SBW connection without extra pins) but AFAIK it is not supported by TI FET's.

https://e2e.ti.com/support/microcontrollers/msp430/f/166/p/746951/2758842#2758842

If msp is only sending UART data (not receiving), then unlimited number of software UART's can be used (aligned by code, without timers and interrupts).

forum.43oh.com/.../1284-software-async-serial-txrx-without-timer

0 Vijay Kolaventy over 6 years ago in reply to zrno soli

Intellectual 870 points

Basically I am connecting the sensors to MSP board to receive sensor data. I also need to periodically retrieve sensor data by sending read command to it through UART which means that I will need both tx and rx

0 Keith Barkley over 6 years ago in reply to Vijay Kolaventy

Guru 43425 points

Yes, you can certainly create a software UART, though you may be limited to low baud rates. Check out the Arduino code for SoftwareSerial which you should be able to adapt.

0 zrno soli over 6 years ago in reply to Vijay Kolaventy

Guru 34943 points

Vijay Kolaventy said:

Basically I am connecting the sensors to MSP board to receive sensor data. I also need to periodically retrieve sensor data by sending read command to it through UART which means that I will need both tx and rx

If your msp device know exactly when it should receive data than it can be handled like on posted link. If receiving of data can happen anytime, in this case you will lose some timers.

https://forum.43oh.com/topic/543-full-duplex-software-uart-for-launchpad/

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MSP430FR6989: Third UART