SCI RX/TX example code for TMS570 Launchpad?

Stephen Holland

Other Parts Discussed in Thread: HALCOGEN, SN75176B

Can anyone share an example CCS project for SCI TX/RX for the launchpad?

I have built a simple application using HALCoGen and the TX works, but I can't for the life of me get the RX to receive anything. Loopback works, so SCI is probably setup right...

Is there some other IO setup required outside of the SCI RX pin enable?

over 12 years ago

0 Hari Pendurty over 12 years ago

TI__Intellectual 1480 points

Hi,

We are looking into this and will get back to you.

Hercules forum support

0 Stephen Holland over 12 years ago in reply to Hari Pendurty

TI__Intellectual 2795 points

I just removed R8 which connects SCI1_RX to U2 (FTDI FT2232HL), and now the SCI RX is working.

Can you confirm this is expected behavior? Why is SCI1_RX connected to the FT2232?

0 Haixiao Weng over 12 years ago in reply to Stephen Holland

TI__Genius 13810 points

Yes.

In the launchpad, we connect the SCI_RX, TX to FTDI chip. The FTDI chip serves as a vitual com port together your PC. Which mean, by default configuration, you can talk to the launchpad through PC hyperterminal. Just like the example project provide in wiki:

http://processors.wiki.ti.com/index.php/Hercules_LaunchPad#Using_the_MibADC_to_collect_Ambient_Light_Sensor_data_percentage

This project output the light sensor AD result to PC hyperterminal.

Regards,

Haixiao

0 Haixiao Weng over 12 years ago in reply to Haixiao Weng

TI__Genius 13810 points

By the way, once you change that resistor settings, you lost some features of the safety demo (firmware comes with the kit).

Regards,

Haixiao

0 Stephen Holland over 12 years ago in reply to Haixiao Weng

TI__Intellectual 2795 points

It would be really nice if the FT2232 TX was configured for open-collector output so the SCI RX could be used elsewhere...

0 Haixiao Weng over 12 years ago in reply to Stephen Holland

TI__Genius 13810 points

True.

I did not find how to configure this pin to open-collector or open-drain. Let me know the method if it is feasurable. Then we can change the BOM in next version.

Thanks,

Haixiao

0 Stephen Holland over 12 years ago in reply to Haixiao Weng

TI__Intellectual 2795 points

Section 4.3.3 of the FT2232H datasheet shows what's needed to make the TX pin multi-drop. The TXDEN pin (FT2232H pin 46) is provided for this purpose. You will need to add a SN75176B.

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SCI RX/TX example code for TMS570 Launchpad?