Base Address Selection

Jumper J10, positions 2-5, is used to configure the base address of the DIO (8255) registers. The 8255 register map occupies 8 bytes of I/O address space, as described in Section 5, I/O Map. Jumper positions 6-9, is used to configure the base address of the counter/timer I/O (9513) registers and the enhanced features registers. The 9513 register map occupies 16 bytes of I/O address space, as described in Section 5, I/O Map. Jumper the locations as shown to set the 8255 and 9513 base addresses.

NOTE: Different address must be selected for the DIO and counter/timer functions.

The example, below, selects a DIO base address of 0040h.

The following example selects a counter/timer base address of 0100h.