User manual

ATHENA CPU User Manual V1.40 Page 21
5. JUMPER SETTINGS
Refer to the Athena board drawing on page 8 for locations of the configuration items mentioned
here. See page 23 for information on configuration J13 for the data acquisition circuit.
5.1 J10: System Configuration
Jumper block J10 is used for configuration of IRQ levels, wait states, ATX power control, and
CMOS RAM.
Serial Port and A/D IRQ Settings
COM3 may be set to IRQ4 or IRQ9. COM4 may be set to IRQ3 or IRQ15. The A/D circuit may be
set to IRQ5 or IRQ4 if COM3 does not use it. In addition, it is possible to set up all 3 circuits to
share IRQ4 or IRQ5. Note that only 1 device can use the ‘shared’ IRQ at one time. True IRQ
sharing where all 3 devices can run simultaneously is not supported here.
ATX Power Control
Athena must have ATX enabled to function properly. This jumper must be installed for the board
to boot when power is applied.
Erasing CMOS RAM
The CMOS RAM may be cleared with a jumper as shown on the next page. This will cause the
CPU to power up with the default BIOS settings. To clear the CMOS RAM, power down the CPU,
install the jumper as shown, return it to its default position, and then power up again.
Before erasing CMOS RAM, write down any custom BIOS settings you have made!
Default Settings