Configuring the Chip Set IRQs

The CPU board comes up wanting to use IRQ5 for the parallel port (LPT). Up through the 12.058 flight, we configured the BIOS to use IRQ7 for LPT, and used IRQ5 for the CM313 RS422 ports.

In 12.058, we experienced a supervisory chip reset at T+39, and after the reboot the BIOS had failed to configure LPT to IRQ7, leaving it set to IRQ5 in conflict with the CM313.

We decided to let the CPU board have IRQ5, and use IRQ7 for the CM313 now.

Special Note: The Vendor's CM313 manual shows a mislabelled board: JP1&3 are reversed, and JP2&4 are reversed. The silkscreen on the actual board is correct.