Getting string on virtual com port.
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‎2018-02-26 03:04 AM
I'm getting a string from a terminal.
int main(void)
{ Set_System(); Set_USBClock(); USB_Interrupts_Config(); USB_Init(); while (1) { if (bDeviceState == CONFIGURED) { CDC_Receive_DATA(); /*Check to see if we have data yet */ if (Receive_length != 0) { if (packet_sent == 1) CDC_Send_DATA ((unsigned char*)Receive_Buffer,Receive_length); Receive_length = 0; } } }}And I see in Receive_Buffer my string. But I want to evaluate every char and to format a string as I need. For example I want to trim all '\n' and '\r' on reception level.
I didn't find a function I get chars from terminal. Where should it be?
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‎2018-02-26 03:24 AM
I didn't find a function I get chars from terminal. Where should it be?
...
CDC_Receive_DATA();
CDC_Send_DATA ((unsigned char*)Receive_Buffer,Receive_length);Obviously from the USB device.
I suggest you need to read the USB spec. then, especially the sections about the CDC device profile.
The air gets a bit thinner there - less people are really familiar with it.
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‎2018-02-26 03:48 AM
I'm a bit confused:
I see in Receive_Buffer my stringIf you can see it in the Receive_Buffer, why can't you just process it from there?
I didn't find a function I get chars from terminal
But you said you have all the characters - in the
Receive_Buffer
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‎2018-02-26 11:49 PM
AvaTar wrote:
The air gets a bit thinner there - less people are really familiar with it.
Thinner? Anorexic!
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‎2018-02-27 12:05 AM
At least you have not lost your senso of humour ... ;)
You intend to use the VCP functionality for debugging / instrumentation, right ?
I would have trouble to justify coding effort, code size impact and performance requirements which a target USB implementation requires.
Except you see it as a kind of apprentice piece.
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‎2018-02-27 12:26 AM
Yep. I gave up on the idea. It was additional nice-to-have feature to a user.
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‎2018-02-27 12:59 AM
A cheap USB-to-Serial converter, with the serial side (TTL) directly connected to TX/RX of the target, are useful where there is no ST-Link V2.1 with VCP.
I mostly use a level shifter that 'boosts' the target TTL levels to RS232 levels - useful if you have a PC with a legacy RS232 interface.
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‎2018-02-27 01:24 AM
This was pointed out repeatedly in the other thread - but you insisted on going the USB/CDC route.
Now you see why we tried so hard to get you to consider the 'external' VCP options ?
(ie, using the ST-Link or an external USB-to-UART).
But, anyhow, it seems that you do have it working - you say you do have a buffer with all the received characters in it.
So why can you not simply process those characters directly from that buffer (or a copy of it)?
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‎2018-02-27 03:20 AM
OK. I format the received string and pass it to a parser.
Now I have another problem. When I process the received string I reply to a user (terminal).
CDC_Send_DATA((uint8_t *)string, strlen(string));
The problem - if I set a break point on the line CDC_Send_DATA and then Step Over - I see the reply on a terminal.
If the code runs free without break point - I see nothing on the terminal. Some synchronization issue I can't bit.
Actually I have a workaround to the problem - to use USB-UART converter or to place FTDI chip on the board.
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‎2018-02-27 03:30 AM
erenburg.evgeny.002 wrote:
Some synchronization issue I can't bit.
Yes, I think so; I think the USB transmissions are probably 'scheduled' somewhere - so you're not (quite) hitting the correct point in the schedule.
Actually I have a workaround to the problem - to use USB-UART converter or to place FTDI chip on the board.
The ST-Link still remains a potential option, too.
If your board doesn't have a suitable ST-Link, and you can't get hold of one that does, the simplest approach is a cable like this:
http://www.ftdichip.com/Images/TTL232RRPI%201_a.jpg
http://www.ftdichip.com/Products/Cables/RPi.htm
The USB end just plugs into your PC, and the UART end just plugs onto the headers on your Discovery board.
Simples!