IBM Personal System/2 65 SX User Manual

System-Board POS Address Map
The following table shows the organization of the I/O address space
used by system-board POS.
Address
(Hex) Function
0094 System-Board Enable/Setup Register
0096 Adapter Enable/Setup Register
0100 POS Register 0O—Reserved
0101 POS Register 1—Reserved
0102 POS Register 2—System-Board I/O Register
0103 POS Register 3—Memory-Enable Register
0104 POS Register 4—Memory-Presence Register
0105 POS Register 5—-Memory-Control Register
0106 Reserved
0107 Reserved
Figure 2-1. System-Board POS I/O Address Map
Card-Selected Feedback
Whenever the system addresses an adapter, the adapter responds by
setting the ‘-card-selected feedback’ signal (-CD SFDBK) to active. -CD
SFDBK is derived from the address decode, driven by a totem-pole
driver, and latched by the system board. It can be read through the
Card-Selected Feedback register at address hex 0091. Diagnostic
and automatic configuration programs use this signal to verify the
operation of an adapter at a given address or DMA port. This signal
must not be active during a setup cycle.
Model 65 POS — October 1990 2-5

IBM Personal System/2 65 SX Specifications

General

Brand	IBM
Model	Personal System/2 65 SX
Category	Desktop
Language	English