XC2200 Derivatives
System Units (Vol. 1 of 2)
System Control Unit (SCU)
User’s Manual
6-85
V2.1, 2008-08
SCU, V1.13
Operating the SWD
Figure 6-18 SWD Power Validation Example
The lower fix threshold V
VAL
defines the absolute minimum operation voltage for the IO
domain. If V
VAL
has not been reached the device is held in reset. When V
DDPB
raises
above V
VAL
, bit
.PON is set.
Note: The physical value for V
VAL
can found in the XC2200 data sheet.
The SWD provides two adjustable threshold levels (LEV1 and LEV2) that can be
individually programmed, via
.LEV1V and SWDCON0.LEV2V, and deliver a
compare value each. The two compare results can be monitored via bits
SWDCON0.L1OK and SWDCON0.L2OK. A reset or interrupt request can be generated
while the voltage level is below or equal/above the configured level of a threshold. If an
V
OP
V
LEV2
V
LEV1
V
VAL
L2OK
L1OK
Power-Off
Power-On
Power-Off
Operation
Operation
Operation
Warning
Fail
V
SS
0V
start-up
reset