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TMS570LS1224: SCI Rx Receive problem: tutorial rx interrupt not working as expected

Geert Jacobs
Prodigy 200 points
Part Number: TMS570LS1224
Other Parts Discussed in Thread: HALCOGEN

Hello,

I want to use the SCI/LIN port as SCI.

This tutorial was followed:

training.ti.com/hercules-how-tutorial-using-sci-uart-communication

The XL2-TMS57012 has pins J11.9 (Tx) and J11.10(Rx) connected to a PC running Teraterm using a TTL RS232 3V3 interface.

Transmission from TMS570 to PC is working fine, but RX under interrupt on TMS570 does not work.
The Rx interrupt / sci_notification is never triggered.
The pin level of the J11.10 (Rx) pin is 3.3V and it seems to be configured as output, even though the Halcogen config settings seem to be fine.

Any idea on what might be wrong?

  • 0
    Prodigy 200 points
    Update: I can see the serial signal on the oscilloscope: it isn't pulled down to zero, signal drops from 3v3 to only about 2V.
  • 0 in reply to Geert Jacobs
    TI__Guru**** 197826 points
    Hello Geert,

    The J10-pin9 and J10-pin10 are also routed to TM4C MCU. The TM4C MCU maps SCI signals to USB, so you can use virtual COM port on your PC to communicate with SCI port on LS12x MCU.

    1. Enable the SCI RX INT under SCI Global in HALCoGen
    2. Enable the SCI interrupt (channel 13 and Channel 27) under VIM channel 0-31
    3. Check VIM RAM to make sure that the right ISRs are assigned to channel 13 and channel 27: linHighLevelInterrupt, and linLowLevelInterrupt
    4. Generate code, and inport the HALCoGen to CCS project
    5. Enable irq interrupt in your main():_enable_IRQ_interrupt_();
    6. Initialize SCI: sicInit(), and TX/RX data through SCI
    7. You should get INT whenever you type character in TeraTerm terminal
  • 0 in reply to QJ Wang
    Prodigy 200 points

    Thanks for replying.

    Using the Virtual COM port makes it work as expected.

    However when using a TTL RS232 3V3 straight on the pins it doesn't work.
    Does this mean that on the XL2-TMS570LS12 the SCI2/LIN cannot be used as a "normal" COM port?

  • 0 in reply to Geert Jacobs
    TI__Guru**** 197826 points
    Hello Geert,

    SCI can be used as "normal" COM port, but an external RS232 transceiver (or UART to RS232 converter) is required.