STK525 Hardware User Guide
3-26
7608A–AVR–04/06
Section 3
Troubleshooting Guide
Figure 3-1 . Troubleshooting Guide
Problem
Reason
Solution
The Green “VCC-ON”
LED is not on
No power supply
Verify the power supply source
Verify the power supply source
STK525 does not work
Connect the DC power supply source, or
USB interface or STK500.
The AT90USBxxx cannot
be programmed
The
STK500 ISP header
is not connected.
Connect a 6-pin flexible cable from
STK500 ISP 6-PIN header to the correct
STK525 ISP header (page 21)
The AVR ISP probe is
not connected
Connect the AVR ISP 6-PIN header to
the correct STK525 ISP header (page
21)
The AVR JTAG ICE
probe is not
connected
Connect the JTAG ICE 10-PIN header to
the correct STK525 JTAG header (page
22)
The memory lock bits
are programmed
Erase the memory before programming
The fuse bits are
wrongly programmed
Check the fuse bits
Programming too fast
with ISP SPI
Check oscillator settings and make sure
it is not set higher than SPI clock
AVR Studio does not
detect the AVR tool used
Serial/USB cable is
not connected, or
power is off
Connect serial cable to RS232 (STK500 -
AVR ISP) and check power connections
Connect serial cable to USB (JATG ICE
MKII, AVR ISPmkIIl) and check power
connections
PC COM port is in
use
Disable other programs that are using
PC COM port.
Change PC COM port
AVR Studio does not
detect COM port.
Disable COM port auto-detection in AVR
Studio file menu. Force COM port to
correct COM port
