SH3000UM SEMTECH [Semtech Corporation], SH3000UM Datasheet - Page 10

• Manufacturer Part Number: SH3000UM
• Manufacturer: SEMTECH [Semtech Corporation]

CPU Supervisor
The SH3003 has two supervisory functions that man-
age the reset of the target processor, a low V
(Brownout Detector) and a Watchdog Timer, see Figure 1.
Both functions are integrated with the Clock Management
System to provide a more complete system solution than
stand-alone components.
The SH3003 has both active high and active low reset
output pins. Both are driven strong to the active state and
weak to the inactive state. This eliminates the need for ex-
ternal pull-ups and allows various reset sources to be con-
nected together in a wire-OR confi guration. (This makes it
simple to set up a manual reset circuit.)
A set of fl ags in the register map indicates the source of
the reset to the system software.
©2006 Semtech Corp.
POWER MANAGEMENT
Application Information
Temperature-
compensated
Reference
Lock Logic
Voltage
V
3
DD
4.40 V
2.30 V
Figure 1. CPU Supervisor --- Low V
Noise Filter
V
V
HIGH
LOW
6-bit Value
Threshold
D/A
(continued)
Hysteresis
50mV
Initialization Logic
TYP
Write-once
.
DD
CLK
32 kHz
R
ESET
DD
monitor
OUT
/ Brownout Detector, Watchdog, Reset logic & Drivers
Not authorized for release outside of Semtech
Mode
10
PWR
32kHz
Low V
The SH3003 drives the reset pins active whenever V
below the value of V
grammable from 2.3V to 4.3V in average steps of 33mV,
see Table 1.
The default V
tory-programmed non-volatile memory. It can be re-pro-
grammed at any time or it can be permanently protected
from any changes by setting the V
protect fl ag.
VBO for min code
(000000)
VBO for max code
(111111)
Step resolution
OK
Parameter
DD
256
Reset
Duration Timer
Reset Logic
U
NDERFLOW
Minimum
BO
7-bit Down Counter
&
value is loaded on power-up from the fac-
7-bit Watchdog
Timeout Value
BO
1
128
, the brownout reset threshold, pro-
0
2.27
Min
Table 1
4.2
Load
V
DD
Typ
20
2.3
4.3
33
R
BO
K
ESET
Reload Control
Lock fl ag or a write-
Alternating Codes
Watchdog
0x5A / 0xC3
20
Max
2.33
www.semtech.com
4.4
K
Logic
SH3003
- DRAFT
From / To
Serial I/O
Units
RST
N
11
10
mV
RST
V
V
DD
is