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MS51
Dec. 17, 2019
Page
226
of 316
Rev 1.01
M
S51
SE
RIES
TE
CHNICA
L REF
ERE
N
CE MA
NU
A
L
T3CON
– Timer 3 Control
Regiser
Address
Reset Value
T3CON
C4H, Page 0
0000_0000b
7
6
5
4
3
2
1
0
SMOD_1
SMOD0_1
BRCK
TF3
TR3
T3PS[2:0]
R/W
R/W
R/W
R/W
R/W
R/W
Bit
Name
Description
4
TF3
Timer 3 overflow flag
This bit is set when Timer 3 overflows. It is automatically cleared by hardware when the program
executes the Timer 3 interrupt service routine. This bit can be set or cleared by software.
3
TR3
Timer 3 run control
0 = Timer 3 is halted.
1 = Timer 3 starts running.
Note that the reload registers RH3 and RL3 can only be written when Timer 3 is halted (TR3 bit
is 0). If any of RH3 or RL3 is written if TR3 is 1, result is unpredictable.
2:0
T3PS[2:0]
Timer 3 pre-scalar
These bits determine the scale of the clock divider for Timer 3.
000 = 1/1.
001 = 1/2.
010 = 1/4.
011 = 1/8.
100 = 1/16.
101 = 1/32.
110 = 1/64.
111 = 1/128.