HYUNDAI MicroElectronics
Release the STOP mode
GMS82512/16/24
the on-chip RAM. External interrupts allow both on-chip
RAM and Control registers to retain their values.
The exit from STOP mode is using hardware reset or exter-
nal interrupt.
Start-up is performed to acquire the time for stabilizing os-
cillation. During the start-up, the internal operations are all
stopped.
To release STOP mode, corresponding interrupt should be
enabled before STOP mode.
Reset redefines all the control registers but does not change
Chip function after event
Event
MCU Status before event
PC
Oscillator Circuit
RESET
Don’t care
Vector
N +1
on
off
on
STOP instruction
External Interrupt
Normal operation
Normal operation
Vector
STOP, I flag = 1
STOP, I flag = 0
Vector
N + 1
on
on
External Interrupt Wake up
Table 16-1 Wake-up and Reset Function Table
16.2 Minimizing Current Consumption
The Stop mode is designed to reduce power consumption.
To minimize current drawn during Stop mode, the user
should turn-off output drivers that are sourcing or sinking
current, if it is practical.
It should be set properly in order that current flow through
port doesn't exist.
First conseider the setting to input mode. Be sure that there
is no current flow after considering its relationship with
external circuit. In input mode, the pin impedance viewing
from external MCU is very high that the current doesn’t
flow.
Note: In the STOP operation, the power dissipation asso-
ciated with the oscillator and the internal hardware is low-
ered; however, the power dissipation associated with the
pin interface (depending on the external circuitry and pro-
gram) is not directly determined by the hardware operation
of the STOP feature. This point should be little current flows
when the input level is stable at the power voltage level
(VDD/VSS); however, when the input level becomes higher
than the power voltage level (by approximately 0.3V), a cur-
rent begins to flow. Therefore, if cutting off the output tran-
sistor at an I/O port puts the pin signal into the high-
impedance state, a current flow across the ports input tran-
sistor, requiring it to fix the level by pull-up or other means.
But input voltage level should be VSS or VDD. Be careful
that if unspecified voltage, i.e. if unfirmed voltage level
(not VSSor VDD) is applied to input pin, there can be little
current (max. 1mA at around 2V) flow.
If it is not appropriate to set as an input mode, then set to
output mode considering there is no current flow. Setting
to High or Low is decided considering its relationship with
external circuit. For example, if there is external pull-up re-
sistor then it is set to output mode, i.e. to High, and if there
FEB. 2000 Ver 1.00
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HYNIX [ HYNIX SEMICONDUCTOR ]
