Auto-Reload Up-Only Mode (ARUO)
In ARUO mode, Timer2 can be configured to count up with a software-defined value to be
reloaded. When reset is applied to the DCEN =0 and CP/RL2=0, Timer2 is at ARUO mode. An
overflow on Timer2 or 1-to-0 transition on T2EX pin will load RCAP2H and RCAP2L contents
onto Timer2, also set TF2 and EXF2, respectively.
OSC/12
T2 pin
C//T2
0
1
0
1
TL2 [7:0]
TH2[7:0]
TF2
TR2
RCAP2L [7:0]
RCAP2H [7:0]
Interrupt
EXF2
T2EX pin
EXEN2
Auto-Reload Up-Down Mode (ARUD)
In ARUD mode, Timer2 can be configured to count up or down. When DCEN =1 and CP/RL2=0,
Timer2 is at ARUD mode. The counting direction is determined by T2EX pin. If T2EX=1, counting
up; otherwise, counting down. An overflow on Timer2 will set TF2 and toggle EXF2. EXF2 cannot
generate interrupt request in this mode. If the counting direction is DOWN, the overflow loads
0xFFFF onto Timer2, and if counting direction is UP, the overflow loads RCAP2H, RCAP2L
contents onto Timer2.
FFH
FFH
EXF2
OSC/12
T2 pin
C//T2
0
1
0
1
TL2 [7:0]
TH2[7:0]
TF2
Interrupt
TR2
RCAP2L [7:0]
RCAP2H [7:0]
T2EX pin
18
MPC89x52A Data Sheet
MEGAWIN
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