Specifications

EPC-8A Hardware Reference

OB1/OB2 Two “option” bytes of configuration information.

All slots not occupied by an EXM module should show an ID of FF and OB1/OB2 of

00 00 indicating that no EXM is present.

Field Description

Slots Identifies the slot to which the configuration information applies:

• EXM Slot 31: Identifies the Flash memory address. Slot 31

refers to the optional resident Flash memory. The ID should

be set to FF if your EPC-8A does not have this feature. If

present, then set the ID to “FD” and Option Byte 1 to “01”.

• Slots 0 through 8: Specifies configuration information for EXM

expansion modules. Consult the appropriate EXM manual for the

correct configuration information for each EXM expansion module

installed. Note that most EXM hardware reference manuals

depict a different BIOS setup from the EPC-8A. The ID/OB1/OB2

information is valid.

When using EXMs with configurable interrupts, DMA

channels, I/O addresses, and/or memory addresses, avoid

conflicts with built-in functions of the EPC-8A. Guidelines are:

- If an interrupt is needed, use IRQ3, IRQ5, IRQ9, IRQ12, or

IRQ15. IRQ7 can be used if the printer port is not being used.

IRQ3 should not be used if the COM2 port is being used.

- Use DMA channels 1, 3, 6, and 7.

- Do not select I/O addresses that conflict with those in the

EPC-8A. A complete list appears in Appendix A. For instance,

I/O addresses in the 300–33F range can be used.

- If the EXM needs to use upper memory addresses, they must

be in the 0C8000–0DFFFF range. Note that the E-page is

used for VMEbus access and is not available.

Figure 3-10. Slot Numbering