GMS81504 Datasheet, PDF (41/54 Pages) List of Unclassifed Manufacturers – CMOS SINGLE-CHIP 8-BIT MICROCONTROLLER

HYUNDAI MicroElectronics
Wake-up and Reset Function Table
Event
Chip Status
before event
RESET
Do not care
STOP instruction
Normal operation
External Interrupt
Normal operation
External Interrupt Wake-up
Stop, I-flag = 1
Stop, I-flag = 0
PC: Program Counter contents after the event.
N: Address of STOP instruction.
GMS81504
Chip function after event
PC
Oscillator
Circuit
Vector
on
N+1
off
Vector
on
Vector
on
N+1
on
Basic interval timer is activated on wake-up. It is
incremented from 00H until FFH then 00H. The count
overflow is set to start normal operation. Therefore,
before STOP instruction, user must be set its relevant
prescaler divide ratio to have long enough time. This
guarantees that crystal oscillator has started and stabi-
lized.
By reset, exit from Stop mode is shown in Figure 34.
Minimizing Current Consumption in
Stop Mode
The Stop mode is designed to reduce power consump-
tion. To minimize current drawn during Stop mode, the
user should turn-off output drivers that are sourcing or
sinking current, if it is practical. Weak pull-ups on port
pins should be turned off, if possible. All inputs should
be either as VSS or at VDD (or as close to rail as
possible). An intermediate voltage on an input pin
causes the input buffer to draw a significant amount of
current.
OSCILLATOR
INTERNAL
CLOCK
STOP MODE
RESET
STOP INSTRUCTION
EXECUTION
tST = 64 ms
at 8 MHz
STABILIZATION TIME
Time can not be control by software.
Figure 34. Timing of Stop Mode Release by Reset
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