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DBAT90USB162 Enhanced
Development Board User’s Manual
2.2.10. ISP and JTAG connectors
Both ISP (6-pin) (P15) and JTAG (10-pin) (P16) connectors offer
identical
functionality
for in-circuit programming and debugging via debugWIRE (RST pin).
If these connectors are in use, it is not recommended (although is possible) to use
corresponding MCU pins as generic I/Os.
ISP and JTAG connectors are pin-to-
pin connected
as follows:
ISP (6-pin)
JTAG (10-pin)
In-circuit
programming
Debugging via
debugWIRE
Pin 3 SCK
Pin 1 TCK
X
Pin 6 GND
Pin 2 GND
X
X
Pin 1 MISO
Pin 3 TDO
X
Pin 2 VCC
Pin 4 VTref
X
X
Pin 5 RST
Pin 6 nSRST
X
X
Pin 4 MOSI
Pin 9 TDI
X
ISP connector pinout:
1 2
MISO
VCC (VTG)
SCK
MOSI
RST
GND
JTAG connector pinout:
1 2
(SCK) TCK
GND
(MISO) TDO
VTref (VCC)
nSRST (RST)
(MOSI) TDI
The JTAG connector is intended for use with devices like JTAGICE mkII and
AVR ONE!, but only offers in-circuit programming and debugging via
debugWIRE as the full JTAG interface is not supported by AT90USB162. The
JTAG 10-pin connector pinout is different from ISP 10-pin connector pinout,
which is not implemented here! DO NOT CONNECT ISP 10-WIRE CABLES TO
THE JTAG CONNECTOR!
The debugWIRE interface uses only one pin, the RST pin, for communication with
the target device. To enable the debugWIRE interface on an AVR device, the
DWEN fuse must be programmed (DWEN = 0). AVR devices featuring debugWIRE
are shipped with the DWEN fuse unprogrammed. ISP or High-Voltage
Programming is required to enable debugWIRE.
In order to use the ISP interface the SPIEN fuse must be programmed.
