Customizing Custom HID descriptor

contact239955_stm1_st · ‎2012-10-09

Posted on October 10, 2012 at 00:12

Hi,

I need to set up a USB connexion between my computer and an STM32 device so I took the Custom HID example provided by ST and I'm trying to make it works as I want.

I just want to send and receive up to 8 bytes so I wrote this

http://pastebin.com/Wxyc8Dkp

(inspired by the example of course).

I can actually send some data from the computer (to light LEDs) but I can't get the value of the ADC.

In my main function I have an infinite loop like this :

while (1) {

ADC_Value[0] = (ADC_ConvertedValue&0xFF00) >> 8;

ADC_Value[1] = ADC_ConvertedValue&0xFF;

buff[0]=0x07;

buff[1]=ADC_Value[0];

buff[2]=ADC_Value[1];

USB_SIL_Write(EP1_IN, buff, 3);

SetEPTxValid(ENDP1);

}

The USB configuration should be ok because with and old (buggy) descriptor I managed to send data but not receive data correctly

Do you see anything wrong in what I'm doing?

Thanks

tsuneo · ‎2012-10-10

Posted on October 10, 2012 at 17:46

while (1) {
// wait until the device is configured
if ( bDeviceState != CONFIGURED ) continue;
// wait until the endpoint finishes
// the last transaction
if ( GetEPTxStatus( ENDP1 ) != EP_TX_NAK ) continue;
ADC_Value[0] = (ADC_ConvertedValue&0xFF00) >> 8;
ADC_Value[1] = ADC_ConvertedValue&0xFF;
buff[0]=0x07;
buff[1]=ADC_Value[0];
buff[2]=ADC_Value[1];
// Send 9 bytes,
// report ID (1 byte) + body (8 bytes)
USB_SIL_Write(EP1_IN, buff, 9);
SetEPTxValid(ENDP1);
}

Also, increase the

wMaxPacketSize

of both of the endpoint descriptors.

0x08

,

/* wMaxPacketSize: 8 Bytes max */

<--- 0x09 Did you claim 9 bytes at CustomHID_Reset() ?

usb_prop.c
 void CustomHID_Reset(void)
{
...
...
/* Initialize Endpoint 1 */
SetEPTxCount(ENDP1, 2); // <---- SetEPTxCount(ENDP1, 9)
SetEPRxCount(ENDP1, 2); // <---- SetEPRxCount(ENDP1, 9)

usb_conf.h
/* EP1 */
/* tx buffer base address */
#define ENDP1_TXADDR (0x100)
#define ENDP1_RXADDR (0x104) // <----(0x10C)

Tsuneo

contact239955_stm1_st · ‎2012-10-10

Posted on October 10, 2012 at 20:59

Thanks for your answer

So I changed what you said in the program but it never goes after this line

if
( bDeviceState != CONFIGURED ) 
continue
;

bDeviceState is equal to 3 (Suspended I think). Can you explain why should I change the

ENDP1_RXADDR

value? edit : Well, I don't know why but know it works perfectly! bDeviceState = configure and I can get and send data without any problems. Thanks a lot for your help

contact239955_stm1_st · ‎2012-10-15

Posted on October 15, 2012 at 15:07

just a little up, I really want to know the meaning of

ENDP1_RXADDR

. Why should I change this? What value to set depending on the context? Thanks

tsuneo · ‎2012-10-15

Posted on October 16, 2012 at 05:39

> So I changed what you said in the program but it never goes after this line

Maybe, hardware problem, like connection of port pins to the USB connector.

> Can you explain why should I change the ENDP1_RXADDR value?

ENDP1_TXADDR and ENDP1_RXADDR macro on usb_conf.h is used to assign packet buffer on USB_RAM to the endpoints. They are starting address of the endpoint buffers. To keep 9 bytes (or more) space for the EP1 TX, the start address of EP1 RX buffer was moved. Because of access limitation of 4 bytes (32bits) boundary on USB_RAM, 0x10C was chosen.

This tuning is required just for STM32F102/103.

Tsuneo

contact239955_stm1_st · ‎2012-10-16

Posted on October 16, 2012 at 15:28

Many thanks for your help, I can finally go on with my project