Zitat:
-B bitclock
Specify the bit clock period for the JTAG interface or the ISP clock (JTAG ICE only). The value is a floating-point number in microseconds. The default value of the JTAG ICE results in about 1 microsecond bit clock period, suitable for target MCUs running at 4 MHz clock and above. Unlike certain parameters in the STK500, the JTAG ICE resets all its parameters to default values when the programming software signs off from the ICE, so for MCUs running at lower clock speeds, this parameter must be specified on the command-line.
Quelle: