Pos Address Map - IBM Personal System/2 50 Technical Reference

P~S
Address Map
The following figure shows the organization of the I/O address space
used by POS. The POS registers are 8-bit registers. Bit 0 of POS
Register 2 and bits 6 and 7 of POS Register 5 are defined. All other
bits in POS Registers 2 through 5 are free-form.
Addre ••
(Hex) Function
0094 System Board Enable/Setup Register
0096 Adapter Enable/Setup Register
0100 POS Register 0- Adapter Identification Byte (Low Byte)
0101 POS Register 1- Adapter Identification Byte (High Byte)
0102 POS Register 2-0ption Select Data Byte 1
Bit 0 is Card Enable.
0103 POS Register 3-0ption Select Data Byte 2
0104 POS Register 4-0ption Select Data Byte 3
0105 POS Register 5-0ption Select Data Byte 4
Bit 7 is the channel check active indicator.
Bit 6 is the channel check status-available indicator.
0106 POS Register 6-Subaddress Extension (Low Byte)
0107 POS Register 7-Subaddress Extension (High Byte)
Figure 2-1. POS 1/0 Address Map
Model 50 POS 2-5