same data displaying differently across 2 UART peripherals

Dino David

Other Parts Discussed in Thread: TMS570LS3137, HALCOGEN

I am writing same data across the two 2 UART's (SCIReg and SCILINReg) of TI -Hercules TMS570LS3137.

I have configured both the UART in the same manner using Halcogen. But unfortunately it does not display correctly.

SCILIN displays correctly the same way as expected. SCI prints some junk value. I have attached the code for reference. Also the snapshot of the display.

3364.sys_main.c

over 10 years ago

0 Anthony F. Seely over 10 years ago

TI__Guru 69070 points

Dino,

the obvious questions is whether you have PUTTY configured the same for both COM4 and COM10.

0 Martin Valencia over 10 years ago

Guru 15185 points

as he said Anthony please check PuTTY settings for both terminals!

if you want another example of sending data by SCI, I leave the next project for you can Download and take it as a guide.

it is for the version of Hercules RM46!

0 Dino David over 10 years ago in reply to Anthony F. Seely

Intellectual 645 points

Yes Anthony. Both the UART's are configured for the same configuration.

0 Dino David over 10 years ago in reply to Martin Valencia

Intellectual 645 points

Hi Martin,

I looked into your project. But it is configured only for scilin which is the default UART of TI hercules. I am using SCI which is extracted from the J11 expansion connector. I configured the NHET1[13] TX (name N2) and NHET1[06] RX (name W3) as UART/SCI in Halcogen for 9600 baud rate. I have attached the sci.h and sci.c file.

Please let me know if my configuration is not correct. As I said I am getting not same data in SCI when compared with SCILIN

0576.sci.c 7028.sci.h

0 Anthony F. Seely over 10 years ago in reply to Dino David

TI__Guru 69070 points

Hi Dino.

What do you have between the J11 expansion connector and the PC. You need some type of level shifter - a direct connection will not work.

0 Dino David over 10 years ago in reply to Anthony F. Seely

Intellectual 645 points

Ohh is it. what type of level shifter? Could you please elaborate on it.
I just connected the Tx and Rx line directly to DB9 Tx and Rx pin of UART cable..

0 Anthony F. Seely over 10 years ago in reply to Dino David

TI__Guru 69070 points

You may have damaged the device, depending on the PC levels since sometimes these can be a negative voltage.

You could get a chip like max2232 and convert the levels to match what is on a DB-9 COM port header from your PC
but you may find it a lot easier to use something like this:
www.adafruit.com/.../284

which will be a USB<>Serial dongle. Just MAKE SURE that the voltages on the launchpad side are 3.3V.

A lot of these things are designed for the arduino which is using pretty old 5V IO levels and 5V IO can damage your Hercules as well.

0 Dino David over 10 years ago in reply to Anthony F. Seely

Intellectual 645 points

I am using a serial to usb converter in the PC's side. Sorry that I did not mentioned in my previous post.

J11--Tx------------> RX-------
Serial to USB converter
J11- RX<-------------TX-------

Hopefully I have not damaged the device .. Do i need level shifter even in this case. Just clarify once again?

0 Anthony F. Seely over 10 years ago in reply to Dino David

TI__Guru 69070 points

What voltage levels are coming out of that serial-USB.
If it was designed for arduino it may be 5V IO in which case there would be a problem.

0 Dino David over 10 years ago in reply to Anthony F. Seely

Intellectual 645 points

The converter which I used is www.aten.com/.../productItem.php. It is mentioned as RS232 compliant. But still I need to convert the TTl level from Hercules to RS232 level which is compatible for PC. Damn!!I never thought of it. Thanks Anthony for notifying me. Hopefully device is not managed..

0 Anthony F. Seely over 10 years ago in reply to Dino David

TI__Guru 69070 points

Yes that is a bad converter to use - it basically gives you the large swing +/- voltage that would come out of the DB9 on your PC.

The one I pointed to from Adafruit would be a good one because it comes out with logic levels and you can adjust the logic level voltage to 3.3V according to the description. You need something that works like that Adafruit adapter.

If it's USB to DB9 generally you can assume it's the wrong kind of adapter for connecting directly to a development kit unless the dev kit also has a DB9 ...

Best Regards,
-Anthony

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same data displaying differently across 2 UART peripherals