z80189 ZiLOG Semiconductor, z80189 Datasheet - Page 46

• Manufacturer Part Number: z80189
• Description: Z80180, Z8s180, Z8l180 Mpu Operation
• Manufacturer: ZiLOG Semiconductor

HALT and Low Power Operation Modes (Z80180-Class
Also, the WAIT input is ignored during RESET. For example, if RESET
is detected while the Z8X180 is in a Wait State (TW), the Wait Stated
cycle in progress is aborted, and the RESET sequence initiated. Thus,
RESET has higher priority than WAIT.
The Z80180 can operate in two different modes:
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and two low-power operation modes:
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In all operating modes, the basic CPU clock (XTAL, EXTAL) must
remain active.
HALT Mode
HALT mode is entered by execution of the HALT instruction (Op Code
76H
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IOSTOP mode
SLEEP
SYSTEM STOP
) and has the following characteristics:
The internal CPU clock remains active
All internal and external interrupts can be received
Bus exchange (BUSREQ and BUSACK) can occur
Dynamic RAM refresh cycle (RFSH) insertion continues at the
programmed interval
I/O operations (ASCI, CSI/O and PRT) continue
The DMAC can operate
HALT mode
Processors Only)
Family MPU User Manual
UM005003-0703
Z8018x
31