Objective Development Forums

I've reworked some of the driver code and while doing this made the size of usbMsgLen a configuration option.

If you want a developer snapshot of this version, please let me know by e-mail (support system for avr-usb). The new version supports several kB of transfer size.

This is not currently supported by the driver. You would have to define usbMsgLen as 16 bit variable and update all accesses accordingly.

USBasp is not compatible to any version of the STK500. It can therefore only be used with avrdude.

However, the USBasp hardware can run the latest version of the AVR-Doper firmware. With this firmware, it has most features of AVR-Doper and is thus compatible to the STK500v2.

Did you check the obvious things:
- fuse bits
- hardware configuration reflected in bootloaderconfig.h
- compiled for correct clock rate
- boot loader enabled by jumper

Sorry about the LED, this is a bug with an #ifdef: The pin is configured as input and if on, the pull-up is enabled, providing a bit of current to the LED. You can fix the problem by adding UTIL_PBIT_SET(ddr, HWPIN_LED); in line 573 of file main.c (directly above UTIL_PBIT_CLR(port, HWPIN_LE...

CDC mode speed can be limited due to aggressive polling by the host. The new version posted yesterday may bring an improvement here. Also, if you have a CPU clock of more than 1 MHz, you can try to pass -B1.1 to avrdude for a higher ISP clock. The -B option is stored in AVR-Doper until you override ...

Please try to add a couple of -v options to the command line of avrdude. It should print more information about data sent and received.

Have you verified that the AVR you are programming is clocked with at least 1 MHz?

Sorry, what I have posted is NOT correct. I've re-read the spec and the resume signal is a differential "1", not SE0. The code should therefore look like this: cli(); USBOUT |= _BV(USB_CFG_DPLUS_BIT); USBDDR |= _BV(USB_CFG_DPLUS_BIT) | _BV(USB_CFG_DMINUS_BIT)...

You must generate a USB reset condition to wake up the PC. This is done with usbDeviceDisconnect(); _delay_ms(10); usbDeviceConnect(); You should only generate the reset if the PC is really in sleep mode. You can find out by checking for start of frame pulses on D-.

These resistors have several functions: * Limit the current if zener diodes are used for voltage limiting on D+ and D-. * Limit the current in case of short circuit or if higher voltage is applied from extern. * To some degree impedance matching to the cable when sending data. * Low pass filter to a...

You don't need USB_CFG_PULLUP_IOPORTNAME in the most recent releases of the driver in order to use usbDeviceDisconnect() and usbDeviceConnect().

1.95 V is far below the limit of 2.5 V. Please use higher voltage and lower power diodes. You should reach AT LEAST 2.5 V.

See the AVR-Doper example. It contains an interface to the UART with custom requests to a HID class device. There's also a command line tool in the avrdebug directory.

If you can use two AVRs: connect them with SPI or whatever (low priority interrupts), use 20 MHz for the frequency measuring AVR and writhe the SPI interrupt routine in assembler. You need to count the number of input pulses during a given period (e.g. 1 second) and the number of CPU clocks taken fo...

You can extend Timer0 in software, but that's not easy. Connect the signal to T1 instead and switch between modes as required. The entire task is not easy. You must be very careful to avoid problems when you are in ICP mode and the frequency increases. I would not recommend this as a beginner's proj...

The schematic should be OK, if the Zener diodes are OK. Please measure the voltage on D- with a voltmeter. It should be well above 2.5 V.