Using timer to do a TX UART port pulling method

Miguel Amezcua Peregrina

Other Parts Discussed in Thread: TMS570LS1224

Im using TMS570LS1224. I need to send some data to the computer but all the SCI pins, I2C and SPI are being used for the encoders or for the PWMs.

I have one and a half CAN free but I did not find any converter to USB

So... I was thinking on using bit bang or pulling to create a TX UART pin to connect it to the PC via bluetooth

So here are my two questions:

do any fo you have a bit bang code for TX??

how can I use the timers for that?? how can I do this but for a TX pin and using timer?

INTCONbits.TMR0IF = 0; //clear interrupt flag
TMR0H = 0xF5; // TMROH must be written first
TMR0L = 0xFC; // F63B=63035 cambia a F5FC

if ((rx1_tick==rx1_oc) && (rx1_inprocess==1)) // llegamos al OC?
{
if ((rx1_i > 0) && (rx1_i < 9))
{
rx1_temp >>= 1;
if (PORTBbits.RB1==1) { rx1_temp |= 0x80;}
rx1_oc+=31; // Calula el proximo valor
rx1_i--; // Decrementa contador de Bit
}
else
{
if (PORTBbits.RB1==1) { rx1_data_ok = 1;}
else {rx1_data_ok=0; }

rx1_tick=0; // Inicializamos contador

rx1_data=rx1_temp;
rx1_inprocess=0;
INTCON3bits.INT1IE=1; // Habilita nuevas Interrumpciones
}
} //Fin RX1

Thanks!!

over 9 years ago

0 Anthony F. Seely over 9 years ago

TI__Guru 68950 points

I assume your N2HET is occupied.

I'd suggest you consider using the CAN and going the USB<>CAN path to get back to the PC. There are a lot of USB CAN dongles on the market for a few hundred dollars.

0 Miguel Amezcua Peregrina over 9 years ago in reply to Anthony F. Seely

Genius 4015 points

Hi Anthony

There are two problems with that.

1)The dollar is way to expensive right know thanks to the actual situation

2)Is a lot of money for me to get one of those.

I need a software solution...

thanks!!

0 Anthony F. Seely over 9 years ago in reply to Miguel Amezcua Peregrina

TI__Guru 68950 points

Hmm, I don't know that I've got a good solution for you.
You could try writing a CAN to UART program for a launchpad, and then use that as a substitute for CAN->USB dongle professionally purchased. But it's probably cheaper for you to purchase the dongle than develop that.

One of our interns published a SPI to UART appnote but you used all your SPI pins, correct?

0 Miguel Amezcua Peregrina over 9 years ago in reply to Anthony F. Seely

Genius 4015 points

actually... thats not a bad idea... I have two boards. And one launchpad... so I could send the data to the other via CAN and then send it via SPI using the code made... that could work

0 Miguel Amezcua Peregrina over 9 years ago in reply to Anthony F. Seely

Genius 4015 points

I got another idea. The board has a JTAG connector and I have the XDS100v2. I could just send the data via JTAG no??
how could I do it?? with printf()??

Thanks!!

0 Anthony F. Seely over 9 years ago in reply to Miguel Amezcua Peregrina

TI__Guru 68950 points

If you use printf() with CCS this is intrusive, your program will break whenever printf is called; it will be automatically restarted so you won't see the breakpoint per se (you don't need to press continue) but during that time your program will not be running. So not good for realtime purposes.

You could implement something using DAP where you read/write a shared range of memory but you would need to implement your own handshake between the PC and the software running on the host computer. DAP on this part can read/write memory over JTAG without stopping the CPU.
AFAIK though we don't have any example of this.

0 Miguel Amezcua Peregrina over 9 years ago in reply to Anthony F. Seely

Genius 4015 points

Actually the data I need to send is just for the testing. So once I get the full arrangement full, is no problem if everything else is paused. I need to retrieve the informtion fron encoders, the duty cycles and the SPI data to make some tests on Matlab and do the controllers for the motors. So I think that way could be usefull for me.
What is DAP???

thanks!!

0 Anthony F. Seely over 9 years ago in reply to Miguel Amezcua Peregrina

TI__Guru 68950 points

Debug Access Port. You can find some idea of what it does here processors.wiki.ti.com/.../Debug_Access_Port_(DAP)

Even though that page is for OMAP there's a similar gadget on Hercules as well as most ARM Cortex devices.

Arm-based microcontrollers

Arm-based microcontrollers forum

Using timer to do a TX UART port pulling method