ST72F324BJ STMICROELECTRONICS [STMicroelectronics], ST72F324BJ Datasheet - Page 62

• Manufacturer Part Number: ST72F324BJ
• Description: 8-bit MCU, 3.8 to 5.5 V operating range with 8 to 32 Kbyte Flash/ROM, 10-bit ADC, 4 timers, SPI, SCI
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

On-chip peripherals
62/188
Figure 34. Exact timeout duration (t
WHERE
t
t
t
CNT = value of T[5:0] bits in the WDGCR register (6 bits)
MSB and LSB are values from the table below depending on the timebase selected by the TB[1:0] bits in the MCCSR
register
To calculate the minimum Watchdog timeout (t
IF
ELSE
To calculate the maximum Watchdog timeout (t
IF
ELSE
NOTE: In the above formulae, division results must be rounded down to the next integer value.
EXAMPLE: With 2ms timeout selected in MCCSR register
min0
OSC2
max0
CNT
CNT
Value of T[5:0] bits in WDGCR register
= (LSB + 128) x 64 x t
= 16384 x t
= 125ns if f
(MCCSR reg.)
t
t
max
<
:
≤
min
TB1 bit
MSB
-------------
MSB
-------------
0
0
1
1
4
4
=
=
t
t
OSC2
min0
max0
OSC2
THEN
THEN
(Hex.)
3F
00
= 8 MHz
+
+
16384
16384
OSC2
t
t
max
min
×
×
(MCCSR reg.)
=
⎛
⎝
=
⎛
⎝
CNT
CNT
TB0 bit
t
t
min0
max0
0
1
0
1
–
–
+
4CNT
---------------- -
+
MSB
4CNT
---------------- -
MSB
16384
min
16384
max
):
Min. Watchdog timeout (ms)
min
):
⎞
⎠
⎞
⎠
×
+
×
+
CNT
(
CNT
and t
(
192
192
Selected MCCSR timebase
×
+
×
+
t
1.496
LSB
t
osc2
t
128
LSB
max
osc2
min
)
)
)
×
×
10ms
25ms
64
2ms
4ms
64
×
×
4CNT
---------------- -
MSB
4CNT
---------------- -
MSB
Max. Watchdog timeout (ms)
×
×
t
t
osc2
osc2
MSB
128.552
20
49
4
8
2.048
t
max
LSB
ST72324B
59
53
35
54