IBM Personal System/2 50 - Section 3. System Board

Section 3. System Board
Description ....... 0.0.00... eee 3-3
| Micro Channel Implementation ....................... 3-3
| Exception Reporting .............-.....20--.020.0. 3-3
Adapter Identification ...................-..00..0. 3-3
Central Arbiter .......... 2.0.0.0... 20 ee 3-3
Arbitration Bus Priority Assignments ............... 3-4
Central Arbiter Programming ..............-...... 3-5
Memory... 1... ee 3-7
Read-Only Memory Subsystem .................00.. 3-7
Random Access Memory Subsystem ................. 3-7
System Memory Maps ...............--.---22005 3-8
System Board Memory Connector ................. 3-9
Real-Time Clock/Complementary Metal-Oxide Semiconductor
RAM .......... ee 3-12
RT/CMOS Address Register and NMI Mask (Hex 0070) .. 3-13
RT/CMOS Data Register (Hex 0071) ............... 3-13
RT/CMOS RAM I/O Operations .................. 3-14
Real-Time Clock Bytes (Hex 000-00D) .............. 3-15
CMOS RAM Configuration ...................-.. 3-19
Miscellaneous System Functions ..................-.. 3-24
Nonmaskable Interrupt ...................2 000005 3-24
System Control Port B (Hex 0061) .............20... 3-24
System Control Port A (Hex 0092) .................. 3-25
Power-On Password ...........0. 0.00000 eae 3-27
Type 2 Serial Port Controller .................0..0.. 3-28
Hardware Compatibility ......................-.02. 3-28
© Copyright IBM Corp. 1989, 1990 3-1