FIXED - mega8 only enumerates after manual reset (PRIZE)

[amx]

Hello,

I have got a problem with the usbasp bootloader: it does not enumerate after plugging in the usb cable (bus powered) but only if I do another manual reset (short the mega8's reset to ground - there is a pull up on the reset-pin).

Since I have some spare boards I am happy to give(/mail) one to the first person whose comment resolves the issue.


Best regards

[ulao]

Show us your schematic, or at lease the usb side of it.

[amx]

It is a pretty standard/basic setup:

Code: Select all

PD2/INT0 --- R68 --- D+
PD3/INT1 --- R68 -+- D-
PD4 --- R1k5------|

I am using an atmega8 at 12MHz and 3.3 Volts.

As mentioned before: enumeration works but not immediately after plugging in the cable.

Code: Select all

#define USB_CFG_IOPORTNAME      D
#define USB_CFG_DMINUS_BIT      3
#define USB_CFG_DPLUS_BIT       2
#define USB_CFG_PULLUP_IOPORTNAME   D
#define USB_CFG_PULLUP_BIT          4

I modified the main() of the usbaspbootloader slightly since I do not have a dedicated button for the bootloader (on by default)

Code: Select all

//  if(bootLoaderCondition()){
        uchar i = 0, j = 0;
        initForUsbConnectivity();
        do {
            usbPoll();
#if BOOTLOADER_CAN_EXIT
            if(requestBootLoaderExit){
                if(--i == 0){
                    if(--j == 0)
                        break;
                }
            }
#endif
//      }while(bootLoaderCondition());  /* main event loop */
      } while(1);
//  }

[amx]

Okay, I fixed it.
I had to comment out the function/macro that initializes the bootloader button.

This is how the main function looks like:

Code: Select all

int __attribute__((noreturn)) main(void)
{
    /* initialize  */
    wdt_disable();      /* main app may have enabled watchdog */
//    bootLoaderInit();
    odDebugInit();
    DBG1(0x00, 0, 0);
#ifndef NO_FLASH_WRITE
    GICR = (1 << IVCE);  /* enable change of interrupt vectors */
    GICR = (1 << IVSEL); /* move interrupts to boot flash section */
#endif
//  if(bootLoaderCondition()){
        uchar i = 0, j = 0;
        initForUsbConnectivity();
        do {
            usbPoll();
#if BOOTLOADER_CAN_EXIT
            if(requestBootLoaderExit){
                if(--i == 0){
                    if(--j == 0)
                        break;
                }
            }
#endif
//      }while(bootLoaderCondition());  /* main event loop */
      } while(1);
//  }
    leaveBootloader();
}

Thanks!

[ulao]

"I had to comment out the function/macro that initializes the bootloader button."
LOL
Yeah... The boot loader is designed to work one "button" is pressed. I overlooked that part , good thing you got it, always better to learn it yourself.

[amx]

Yeah, now it works.

ulao, since you were the only one who replied, if you want a board pm me a mail address.

[ulao]

Oh thx so much for the offer but that wont be necessary. I dont think this forum has a pm anyways. I'm just happy to help.

[vouvoume]

Hi

Classic ATmega8 is designed for 5V. So 3.3V may be not safe?

If you are still interested, maybe take a look into a recent fork of USBaspLoader: https://github.com/baerwolf/USBaspLoader
This version has a revised bootloader condition.

Best regards