Aduc812 – Analog Devices ADuC812 User Manual
Page 30
REV. B
ADuC812
–30–
User configuration and control of all Timer operating modes is
achieved via three SFRs, namely:
TMOD, TCON:
Control and configuration for
Timers 0 and 1.
T2CON:
Control and configuration for
Timer 2.
TMOD
Timer/Counter 0 and 1 Mode
Register
SFR Address
89H
Power-On Default Value
00H
Bit Addressable
No
e
t
a
G
T
/
C
1
M
0
M
e
t
a
G
T
/
C
1
M
0
M
Table XVI. TMOD SFR Bit Designations
Bit
Name
Description
7
Gate
Timer 1 Gating Control.
Set by software to enable timer/counter 1 only while
INT1 pin is high and TR1 control bit is set.
Cleared by software to enable timer 1 whenever TR1 control bit is set.
6
C/T
Timer 1 Timer or Counter Select Bit.
Set by software to select counter operation (input from T1 pin).
Cleared by software to select timer operation (input from internal system clock).
5
M1
Timer 1 Mode Select Bit 1 (Used with M0 Bit).
4
M0
Timer 1 Mode Select Bit 0.
M1
M0
0
0
TH1 operates as an 8-bit timer/counter. TL1 serves as 5-bit prescaler.
0
1
16-Bit Timer/Counter. TH1 and TL1 are cascaded; there is no prescaler.
1
0
8-Bit Auto-Reload Timer/Counter. TH1 holds a value which is to be
reloaded into TL1 each time it overflows.
1
1
Timer/Counter 1 Stopped.
3
Gate
Timer 0 Gating Control.
Set by software to enable timer/counter 0 only while
INT0 pin is high and TR0 control bit is set.
Cleared by software to enable Timer 0 whenever TR0 control bit is set.
2
C/T
Timer 0 Timer or Counter Select Bit.
Set by software to select counter operation (input from T0 pin).
Cleared by software to select timer operation (input from internal system clock).
1
M1
Timer 0 Mode Select Bit 1.
0
M0
Timer 0 Mode Select Bit 0.
M1
M0
0
0
TH0 operates as an 8-bit timer/counter. TL0 serves as 5-bit prescaler.
0
1
16-Bit Timer/Counter. TH0 and TL0 are cascaded; there is no
prescaler
1
0
8-Bit Auto-Reload Timer/Counter. TH0 holds a value which is to
be reloaded into TL0 each time it overflows.
1
1
TL0 is an 8-bit timer/counter controlled by the standard timer 0 control
bits. TH0 is an 8-bit timer only, controlled by Timer 1 control bits.