SAB80C515A-5 SIEMENS [Siemens Semiconductor Group], SAB80C515A-5 Datasheet - Page 46

• Manufacturer Part Number: SAB80C515A-5
• Description: 8-Bit CMOS Single-Chip Microcontroller Family
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

Special Function Register WDTREL (Address 086 H )
Bit No.
Bit
WDTREL.7
WDTREL.6
to
WDTREL.0
Reset value of WDTREL is 00 H .
Immediately after start (see next section for start procedure), the Watchdog Timer is initialized to
the reload value programmed to WDTREL.0-WDTREL.6. After an external HW reset (or power-on
reset, or HW Power Down) register WDTREL is cleared to 00 H . The lower seven bits of WDTREL
can be loaded by software at any time.
Examples (given for 12 and 18 MHz oscillator frequency):
WDTREL
00 H
80 H
7F H
Semiconductor Group
086 H
MSB
7
Function
Prescaler select bit.
When set, the watchdog timer is clocked through an additional divide-by-16
prescaler (see figure 12).
Seven bit reload value for the high-byte of the watchdog timer.
This value is loaded to the WDT when a refresh is triggered by a consecutive
setting of bits WDT and SWDT.
f
65.535 ms
1.1 s
512 s
OSC
6
= 12 MHz
Time-out Period
Watchdog Timer Reload Register
5
f
43.690 ms
0.73 s
341 s
OSC
4
= 18 MHz
5-13
3
On-Chip Peripheral Components
Comments
This is the default value and coincides
with the watchdog period of the SAB
80C515
maximum time period
minimum time period
2
1
LSB
0
WDTREL