Z8PE003 Datasheet, PDF (23/48 Pages) Zilog, Inc. – FEATURE-ENHANCED Z8PLUS 1K ROM ONE-TIME PROGRAMMABLE (OTP) MICROCONTROLLER

ZiLOG
Z8PE003
Z8Plus OTP Microcontroller
STOP MODE OPERATION
The STOP mode provides the lowest possible device stand-
by current. This instruction turns off the on-chip oscillator
and internal system clock.
To enter the STOP mode, the Z8Plus only requires a STOP
instruction. It is not necessary to execute a NOP instruction
immediately before the STOP instruction.
6F STOP ;enter STOP mode
The Z8Plus provides a dedicated Stop-Mode Recovery
(SMR) circuit. In this case, a low-level applied to input pin
PB0 (I/O Port B, bit 0) triggers an SMR. To use this mode,
pin PB0 must be configured as an input and the special func-
tion selected before the STOP mode is entered. The Low
level on PB0 must be held for a minimum pulse width
T_WSM. Program execution starts at address 20h, after the
POR delay.
The STOP mode is exited by any one of the following resets:
POR or a Stop-Mode Recovery source. At reset generation,
the processor always restarts the application program at ad-
dress 0020H, and the STOP mode flag is set. Reading the
STOP mode flag does not clear it. The user must clear the
STOP mode flag with software.
Note: Failure to clear the STOP mode flag can result in unde-
fined behavior.
Notes: 1. The PB0 input, when used for Stop-Mode Recovery,
does not initialize the control registers.
The STOP mode current (I_CC2) is minimized when:
• V_CC is at the low end of the device’s operating range
• Output current sourcing is minimized
• All inputs (digital and analog) are at the Low or High
rail voltages
2. For detailed information about flag settings, see the
Z8Plus User’s Manual.
DS007500-Z8X0399
PRELIMINARY
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