IBM System/34 Maintenance Manual page 179

Main Storage Processor Cards
Main Storage Processor Data. Flow
• Arithmetic logic unit (AlU) gate
• local storage register (lSR) gate
• local storage register (lSR)
• X-high register, Y register, main storage address
register (MSAR), X-low register
• Arithmetic logic unit (ALU), parity predict and control
bits
• Main storage gate
• Gating circuits
• Parity checks-lSR gate and main storage gate
Main Storage Processor Control
• Operation register
Q
register
• Q
backup register
• Control gate
• Program status register (PSR)
• Status bytes
• Status gate
• Configuration control register (CCR)
8
• Data flow control
Control gate selection
Arithmetic logic unit (AlU) gate selection
Main storage gate selection
Gate selection
X-low 'register and Y register selection
Clock main storage processor X-high register,
X-low register, Y register, and main storage
address register (MSAR)
local storage register (lSR) selection
Arithmetic logic unit (AlU) bits and carry in
• Decode system instructions
• Clocks
• Control for control gate, local storage register (lSR)
gate, and main storage gate checks
• Main storage controls
• I nterface to the control processor
Storage Select and Repower Card
The function of this card is to repower the control,
address, and data lines between the main storage
processor and the lower and upper 128K bytes of main
storage. The following lines are repowered:
• Control
MS write pulse low and high
MS data strobe high
Write main storage
• MSAR address bits 10-15
• Data
15-210
Data in bits 8-15, P
- Data out bits 8-15, P
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