Objective Development Forums 2013-05-11T22:51:10+02:00 https://forums.obdev.at/app.php/feed/topic/8409 2013-05-11T22:51:10+02:00 2013-05-11T22:51:10+02:00 https://forums.obdev.at/viewtopic.php?t=8409&p=25255#p25255 <![CDATA[Re: Send Integer to PC with usbMsgPtr]]>

Code: 

        int temp = (buffer[0] << 8) | buffer[1];

        printf("Temperature: %i\n", temp);


That was what I did too... I guess I will try it again.

Statistics: Posted by Guest — Sat May 11, 2013 10:51 pm

]]> 2013-05-06T16:30:38+02:00 2013-05-06T16:30:38+02:00 https://forums.obdev.at/viewtopic.php?t=8409&p=25234#p25234 <![CDATA[Re: Send Integer to PC with usbMsgPtr]]>
Remember: "setupData" needs to be at least 8 bytes.


At host end of course you need to do:
    int result = ((int)buffer[3]<<8) | ((int)buffer[2]);
    printf("%i\n",result);

So long

Statistics: Posted by Guest — Mon May 06, 2013 4:30 pm

]]> 2013-05-06T15:57:15+02:00 2013-05-06T15:57:15+02:00 https://forums.obdev.at/viewtopic.php?t=8409&p=25233#p25233 <![CDATA[Re: Send Integer to PC with usbMsgPtr]]>
In my very first post:

Code: 

  
int temp = 255;
t_char[2] = {0};
t_char[0] = (temp >> 8) & 0xff;
t_char[1] = (temp) & 0xff;
usbMsgPtr = t_char;
return sizeof(t_char);


Which does not work.

So long, nictex

Statistics: Posted by Guest — Mon May 06, 2013 3:57 pm

]]> 2013-05-06T14:25:08+02:00 2013-05-06T14:25:08+02:00 https://forums.obdev.at/viewtopic.php?t=8409&p=25232#p25232 <![CDATA[Re: Send Integer to PC with usbMsgPtr]]> On the host side you again could decode the single bytes together to an int.

    usbMsgPtr = (usbMsgPtr_t)setupData;
    switch (rq->bRequest) {
    [...]
    case PSCMD_CALL_GETBUFFERSIZE: {
    setupData[0] = rq->bRequest;
    setupData[1] = PSCMD_RETN_OKAY;
    setupData[2] = (singlebuffersize)&0xff;
    setupData[3] = (singlebuffersize)>>8;
    cli();
    [...]

Best regards

Statistics: Posted by Guest — Mon May 06, 2013 2:25 pm

]]> 2013-05-06T09:30:14+02:00 2013-05-06T09:30:14+02:00 https://forums.obdev.at/viewtopic.php?t=8409&p=25231#p25231 <![CDATA[Re: Send Integer to PC with usbMsgPtr]]>
as far as I know both AVR-gcc and gcc on windows use little ebdian. Besides that I also bit shifted the numbers in another way so that it should resemble endianness conversion.

How do I really send an integer number now? The method i've put into my last post does not work!

so long, nictex

Statistics: Posted by Guest — Mon May 06, 2013 9:30 am

]]> 2013-05-03T12:52:30+02:00 2013-05-03T12:52:30+02:00 https://forums.obdev.at/viewtopic.php?t=8409&p=25212#p25212 <![CDATA[Re: Send Integer to PC with usbMsgPtr]]>
Your AVR has an "other understanding" of integer, than your host.

One thing is the endianness (http://en.wikipedia.org/wiki/Endianness).
Your AVR is BIG endian - your PC little endian.
Also your AVR uses just 16bit (??) for int, while your PC uses 4 bytes.

As a convention data always is transmitted in little endian trough networks.
(Usually your PC has much more CPU power to transform it in its own format,
than little microcontrollers have.)

To simplify platform independent code see http://www.gnu.org/software/libc/manual ... Order.html .
(Use hton on the AVR side and ntoh on the PC side)

To avoid type misinterpretation on both sides use "#include <stdint.h>" and then the std-type uint32_t or int32_t.
(http://www.gnu.org/software/gnulib/manu ... 002eh.html AND
http://www.nongnu.org/avr-libc/user-man ... tdint.html)

Best regards

Statistics: Posted by Guest — Fri May 03, 2013 12:52 pm

]]> 2013-05-02T13:36:18+02:00 2013-05-02T13:36:18+02:00 https://forums.obdev.at/viewtopic.php?t=8409&p=25208#p25208 <![CDATA[Re: Send Integer to PC with usbMsgPtr]]>

Okay, could you provide me with some functioning code?

I now did this:

Code: 

      case USB_GET_TEMP:
         {
            usbMsgPtr = temp;
            return sizeof(temp);
         }


But how do I get the value then in my PC program?
I am using this code http://codeandlife.com/2012/02/04/avr-attiny-usb-tutorial-part-4/
How do I get the 2 byte integer into the PC? It seems that you do not really understand my problem. Have you tried doing it?
I cannot just do this:

Code: 

       int16_t temp;
        nBytes = usb_control_msg(handle,
            USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_ENDPOINT_IN,
            USB_GET_TEMP, 0, 0, temp, sizeof(temp), 5000);
        printf("Bytecount: %d, Buffer: %i\n", nBytes, temp);


It just does not work.

So long, nictex

Statistics: Posted by Guest — Thu May 02, 2013 1:36 pm

]]> 2013-04-28T16:06:12+02:00 2013-04-28T16:06:12+02:00 https://forums.obdev.at/viewtopic.php?t=8409&p=25198#p25198 <![CDATA[Re: Send Integer to PC with usbMsgPtr]]>
But for usbMsgPtr it is just imprtant to have at least 8 bytes accessable memory.
If it is memory of "type" int, char or void - not even the programming language really cares.

Important is just the memory (space).

For formated output (like printf) you need to tell the function how to "interpret" the memory. If the memory contains "data" of an integer you need to use %i instead %s.

Best regards,

Statistics: Posted by Guest — Sun Apr 28, 2013 4:06 pm

]]> 2013-04-27T16:41:28+02:00 2013-04-27T16:41:28+02:00 https://forums.obdev.at/viewtopic.php?t=8409&p=25192#p25192 <![CDATA[Re: Send Integer to PC with usbMsgPtr]]>
did you understand what I was trying to do with the code in my first post?
Can I just point the usbMsgPtr to a 16bit variable instead of an array of 8bit variables??? (Char array) Because if you read through my first posted code segments you See that I bit shifted the integer into a char array of size 2 and then shifted it back in the PC program. So you think I just Have To do usbMsgPtr = temp; ?

so long, nictex

Statistics: Posted by Guest — Sat Apr 27, 2013 4:41 pm

]]> 2013-04-27T02:30:17+02:00 2013-04-27T02:30:17+02:00 https://forums.obdev.at/viewtopic.php?t=8409&p=25191#p25191 <![CDATA[Re: Send Integer to PC with usbMsgPtr]]>

Code: 

printf("Bytecount: %d, Buffer: %s\n", nBytes, buffer);


Then you should not do a %s, but a something like an %i instead?

Statistics: Posted by Guest — Sat Apr 27, 2013 2:30 am

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