IBM Personal System/2 50 Technical Reference page 7

Figures
1-1. Model and Submodel Bytes . . . . . . . . . . . . . . . . . . . 1-3
1-2. System Board Devices and Features ............. 1-4
1-3. System Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
1-4. System Board I/O Address Map ................ 1-6
1-5. Performance Specifications - Type 1 System Board .. 1-7
1-6. Performance Specifications - Type 2 System Board .. 1-8
1-7. Physical Specifications . . . . . . . . . . . . . . . . . . . . . . 1-9
2-1. POS I/O Address Map . . . . . . . . . . . . . . . . . . . . . . . 2-5
2-2. Card Selected Feedback Register (Hex 0091) ....... 2-6
2-3. System Board Enable/Setup Register (Hex 0094) ..... 2-7
2-4. System Board POS Register 2 (Hex 0102) .......... 2-8
2-5. Parallel Port Select Bits . . . . . . . . . . . . . . . . . . . . . 2-8
2-6. System Board POS Register (Hex 0103) ........... 2-9
2-7. Adapter Enable/Setup Register (Hex 0096) ........ 2-10
3-1. Arbitration Bus Priority Assignments ............. 3-4
3-2. Arbitration Register, Write to Hex 0090 ........... 3-5
3-3. Arbitration Register, Read Hex 0090 ............. 3-5
3-4. System Memory Map . . . . . . . . . . . . . . . . . . . . . . . 3-8
3-5. System Board Memory Connector, Type 1 ......... 3-9
3-6. System Board Memory Connector, Type 2 ........ 3-10
3-7. Presence Detect Encoding . . . . . . . . . . . . . . . . . . . 3-11
3-8. RT/CMOS RAM Address Map . . . . . . . . . . . . . . . . . 3-12
3-9. RT/CMOS Address Register and NMI Mask (Hex 0070) 3-13
3-10. RT/CMOS Data Register (Hex 0071) ............. 3-13
3-11. Real-Time Clock Bytes . . . . . . . . . . . . . . . . . . . . . 3-15
3-12. Status Register A . . . . . . . . . . . . . . . . . . . . . . . . . 3-16
3-13. Status Register B . . . . . . . . . . . . . . . . . . . . . . . . . 3-16
3-14. Status Register C . . . . . . . . . . . . . . . . . . . . . . . . . 3-18
3-15. Status Register D . . . . . . . . . . . . . . . . . . . . . . . . . 3-18
3-16. Diagnostic Status Byte . . . . . . . . . . . . . . . . . . . . . 3-19
3-17. Diskette Drive Type Byte . . . . . . . . . . . . . . . . . . . . 3-20
3-18. Diskette Drive Type Byte (Bits 7 - 4) ............ 3-21
3-19. Diskette Drive Type Byte (Bits 3 - 0) ............ 3-21
3-20. Equipment Byte . . . . . . . . . . . . . . . . . . . . . . . . . . 3-22
3-21. Equipment Byte (Bits 7, 6) . . . . . . . . . . . . . . . . . . . 3-22
3-22. Equipment Byte (Bits 5, 4) . . . . . . . . . . . . . . . . . . . 3-22
3-23. System Control Port B (Write) ................. 3-25
3-24. System Control Port B (Read) ................. 3-25
3-25. System Control Port A (Hex 0092) .............. 3-26
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