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Hello everybody, I am currently programming a Tiva C series, TM4C123GH6PM Evaluation Board from TI.
I need to send a relatively large amount of data to the virtual com of the PC. This board has an integrated virtual com feature (as soon as you plug the usb, and install the drivers, a virtual COM is generated).
I've configured the UART0 peripheral, and used the UARTprintf command, and it works properly.
But, as far as I know, this is only for strings/chars types. I need to send an array of 300 elements, made by 16-bit registers.
I've read about the UART, and the uDMA feature. I don't know if activating the DMA is necessary in this type of transfers, or if it's enough with a while loop. I've seen a lot of code-examples, and read the TI forum, but I'vve found nothing like what I need. In every example I saw, they just use the UART to echo what you sent from the PC.
Can anybody give me a hint on where to start? I'm not asking for anybody to solve this for me, only perhaps to point me in the right direction. Thanks a lot for taking the time to read this. Kind regards
Martín
Hello, Per. Thanks for your prompt response. I've managed to get the array transmition working. But I've got some doubts that arised from your explanations.
Since the transmit register is small, and the UART can only send a limited number of data bits, does this mean that all the data HAS to be sent in an 8-bit byte format?
If, for example, I've used the ADC to obtain an array of 50 samples of uint32_t type... let's say smth like this:
uint32_t pui32ADC0Value[1]; uint32_t Valoresleidos[50];
....(there's a while loop here that only takes 50 samples...)
// Read ADC Value. ADCSequenceDataGet(ADC0_BASE, 3, pui32ADC0Value); // Assemble an array with 50 read values. ADCReadValues[i]= pui32ADC0Value[0]; i++;
.....(and later I do...)
for (unsigned j = 0; j < 50; ++j) { UARTprintf("%d\r;", ADCReadValues[j]); }
Can I just transmit the uint32_t values through the UART? Will the data transmitted be OK? Or do I have to convert them to binary, split them into 8-bits, and send them one by one? Luckily, I don't have to transmit floating point, or strings. Only signed integers of 16 or 32 bits.
Again, thanks for your support. Kind regards
You have to split your 32-bit values into a sequence of 8-bit or smaller values.
But printf() is one way of doing that - it converts the binary values into a sequence of one or more ASCII characters - and every ASCII character will fit, one at a time, in the 8-bit transmit register of the UART.
Are you sure you want to use "\r" for your line endings? It isn't a very common use. "\n" or "\r\n" are way more used. And for systems using \r\n, the \n in the C code will normally be auto-converted into \r\n in the resulting output.
Per, thanks again. You've been most helpful. I'm still considering the use of "\r" or "\r\n". The thing is, I've got to pick up the data using a software. It's still to be seen which way is better for the software programmer.
If I understand you correctly then... if I have a uint32_t data obtained by the ADC, and I use the UARTprintf() command, then the UART automatically converts the data to ASCII, and sends it in "8-bit packages"?
Do I have to "re-ensamble" the data on the Rx side? I'm using hyperTerminal to monitor the serial port, and as far as I can tell, the data is arriving correctly.
Regards.