ML51/ML54/ML56
Sep. 01, 2020
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Rev 2.00
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5
6 S
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TECHNI
CA
L
RE
F
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NC
E
M
A
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ML51/M
L54
/M
L56
Series
Tec
hnical Reference
Manual
TF0
(TF1)
TH0 (TH1)
TL0 (TL1)
Timer Interrupt
0
7
0
7
T0 (T1) pin
T0OE
(T1OE)
0
1
T0 (T1) pin
C/T
GATE
TR0 (TR1)
F
SYS
INT0 (INT1) pin
1/12
0
1
T0M
(T1M)
Figure 6.5-3 Timer/Counters 0 and 1 in Mode 2
Mode 3 (Two Separate 8-Bit Timers)
6.5.2.4
Mode 3 has different operating methods for Timer 0 and Timer 1. For Timer/Counter 1, Mode 3 simply
freezes the counter. Timer/Counter 0, however, configures TL0 and TH0 as two separate 8 bit count
registers in this mode. TL0 uses the Timer/Counter 0 control bits C/T, GATE, TR0, INT0, and TF0.
The TL0 also can be used as a 1-to-0 transition counter on pin T0 as determined by C/T (TMOD.2).
TH0 is forced as a clock cycle counter and takes over the usage of TR1 and TF1 from Timer/Counter
1. Mode 3 is used in case that an extra 8 bit timer is needed. If Timer/Counter 0 is configured in Mode
3, Timer/Counter 1 can be turned on or off by switching it out of or into its own Mode 3. It can still be
used in Modes 0, 1 and 2 although its flexibility is restricted. It no longer has control over its overflow
flag TF1 and the enable bit TR1. However Timer 1 can still be used as a Timer/Counter and retains
the use of GATE, INT1 pin and T1M. It can be used as a baud rate generator for the serial port or
other application not requiring an interrupt.
TF0
TH0
TL0
Timer 0 Interrupt
0
7
0
7
TF1
Timer 1 Interrupt
TR1
GATE
TR0
INT0 pin
T0 pin
T0OE
T1 pin
T1OE
0
1
T0 pin
C/T
F
SYS
1/12
0
1
T0M
Figure 6.5-4 Timer/Counter 0 in Mode 3