Rainbow Electronics T89C5121 - Manual (Page 15)

15
A/T8xC5121
4164G–SCR–07/06
Figure 9. Power-Up and Steady-state Conditions Monitored
Such device when it is integrated in a microcontroller, forces the CPU in reset mode
when V
DD
reaches a voltage condition which is out of the specification.
The thresholds and their functions are:
• V
PFDP
: the output voltage of the regulator has reached a minimum functional value
at the power-up. The circuit leaves the RESET mode.
• V
PFDM
: the output voltage of the regulator has reached a low threshold functional
value for the microcontroller. An internal RESET is set.
Glitch filtering prevents the system from RESET when short duration glitches are carried
on V
DD
power supply.
The electrical parameters V
PFDP
, V
PFDM
, t
rise
, t
fall
, t
G
are specified in the DCparameters
section.
Power-up
Steady-state Condition
DV
CC
Reset
VPFDP
VPFDM
t
G
V
CC
t
rise
t
fall
Power-down