ZiLOG System 8000 Hardware Reference Manual

HRM
Zilog
HRM
point to the memory location. The memory controller ignores
the least-significant address bit (ADOO); the state of
address bit AD01 tells the memory controller to st~re the
current word (16-bits) in either the upper half or lower
half of the double-word space in memory. Figure 4-13 shows
the path of two 16-bit words, E and F. The controller
stores word E in the word 0 location (bits 31 to 16) and
stores word F in the word 1 location (bits 15 to 0)). All
word-size transfers must occur only on a word boundary.
4.5.5.3 Long-Word Translation: Long words (Fig\lre 4-14 con-
tain four bytes (32 bits) and occupy the entire width of the
ZBI and memory controller, and end up in a location in
memory. The 22 most-significant address bits point to the
location; the controller ignores the two least-significant
bits, ADOO and AD01.
4.6. Systeull Reset
A system reset can be generated from a power-up circuit on
the CPU board or by the RESET button on the front panel of
the System 8000. The power-up reset circuit makes certain
that all functions in the system start in an orderly manner.
The RESET button on the front panel is disabled by the
ON/LOCK keylock switch when in the LOCK position.
When the system is reset, the following actions occur:"
All eight serial I/O channels are disabled.
control registers must be initialized.
All SIO
2) All CTC channels stop counting and all interrupt-enable
bits are cleared. CTC control registers must be ini-
tialized.
3) Parallel data is inhibited.
4.7. Non-Maskable Interrupts (NMI)
Non-maskable interrupts are typically reserved for external
events that require immediate attention. They cannot be
disabled (masked) by software. The System 8000 provides
three sources of NMI: manual NMI, power-fail NMI, and a
double-bit non-correctable ECC memory error NMI.
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ZiLOG System 8000 Specifications

General

Brand	ZiLOG
Model	System 8000
Category	Desktop
Language	English