C868_02 Datasheet, PDF (170/244 Pages) Infineon Technologies AG – 8 - Bit CMOS Microcontroller

C868
Reset and System Clock Operation
5.3
Brownout
An on-chip analog circuit detects brownout, if the supply voltage V_DDC dips below the
threshold voltage V_THRESHOLD momentarily while RESET pin is high. If this detection is
active for tbd usec then the device will reset. When supply voltage V_DDC recovers by
exceeding V_THRESHOLD while RESET is high, the reset is released once PLL is locked
for 4096 clocks. Bit BO in the PMCON0 register is set when brownout detected if
brownout detection was enabled, this bit is cleared by hardware reset RESET and
software. All ports are tristated during brownout.
The V_THRESHOLD has a nominal value of 1.47V, a minimum value of 1.1V and a
maximum value of 1.8V.
PMCON0
Wake-up Control Register
[Reset value: XXX000000_B]
7
6
5
4
3
2
1
0
-
-
-
EBO
BO
SDSTAT
WS
EWPD
r
r
r
rw
rw
rh
rw
rw
The functions of the shaded bits are not described here
Field
BO
EBO
-
Bits
3
4
[7:5]
Typ Description
rw Brownout Status Bit.
0 : Brownout not detected.
1 : Brownout detected before the last power on if EBO was
set before the occurence of brownout..
This bit is set by hardware only, it is cleared by hardware
reset and software.
rw Enable Brownout detect.
0: Brownout module is disabled. Occurence of brownout
will not cause an internal reset.
1: Occurence of brownout will cause an internal reset and
BO will be set.
r reserved;
returns ’0’ if read; should be written with ’0’;
User’s Manual
5-4
V 0.4, 2002-01