Installation Manual

IRIS OEM Edition Hardware Reference Manual
Doc. # 7430-0549-01 Rev. B Page 29
9 Atmega1281 Fuses
The ATMega1281V processor on the OEM edition modules has many programmable fuses to
control various parameters. Refer to Atmel’s technical information for the ATMega1281V for a
complete discussion of the fuses. There are two fuses that MoteWorks users should be aware of
as setting these fuses incorrectly will cause the unit to not operate correctly.
9.1 JTAG fuse
This fuse enables users to use the Atmel JTAG pod for in-circuit code debugging. Units are
shipped with JTAG enabled. As discussed in the previous section on battery voltage monitoring,
if JTAG is enabled, it will cause inaccurate measurements on ADC channel 7.
9.2 Using UISP to set fuses
The UISP utility used to download code to the OEM edition modules via a programming board
can also be used to set and unset fuses of the Atmel
®
ATMega1281.
Table 9-1. UISP Commands for Setting the ATMega1281’s Fuses
Action Command
Disable JTAG fuse
uisp -dprog=<programmer> --wr_fuse_h=0xd9
Enable JTAG fuse
uisp -dprog=<programmer> --wr_fuse_h=0x19
Enable native 128 mode
uisp -dprog=<programmer> --wr_fuse_e=0xff
Use internal clock
uisp -dprog=<programmer> --wr_fuse_l=0xc2
Use external clock
uisp -dprog=<programmer> --wr_fuse_l=0xff
<programmer> is the device you are using to interface to the Mote from a computer. The current options
are dapa (for an MIB500), mib510 for a MIB510; and EPRB for a MIB600.
Users can also edit the file called profile in the cygwin/etc/ directory and enter an alias. One
example is this alias to disable the JTAG fuse:
alias fuse_dis="uisp -dprog=<programmer> --wr_fuse_h=0xd9"
Therefore, when fuse_dis and is entered into a Cygwin command line, the script will be
executed.