FlashFlex MCU
SST89E516RD2 / SST89E516RD
SST89V516RD2 / SST89V516RD
Data Sheet
5.0 TIMERS/COUNTERS
5.1 Timers
The device has three 16-bit registers that can be used as
either timers or event counters. The three timers/counters
are denoted Timer 0 (T0), Timer 1 (T1), and Timer 2 (T2).
Each is designated a pair of 8-bit registers in the SFRs.
The pair consists of a most significant (high) byte and least
significant (low) byte. The respective registers are TL0,
TH0, TL1, TH1, TL2, and TH2.
TABLE
5-2: Timer/Counter 1
TMOD
Mode
0
Used as
Timer
1
2
3
0
Used as
Counter
1
2
3
Function
13-bit Timer
16-bit Timer
8-bit Auto-Reload
Does not run
13-bit Timer
16-bit Timer
8-bit Auto-Reload
Not available
Internal
Control
1
00H
10H
20H
30H
40H
50H
60H
-
External
Control
2
80H
90H
A0H
B0H
C0H
D0H
E0H
-
T5-2.0 1273
5.2 Timer Set-up
Refer to Table 3-8 for TMOD, TCON, and T2CON registers
regarding timers T0, T1, and T2. The following tables pro-
vide TMOD values to be used to set up Timers T0, T1, and
T2.
Except for the baud rate generator mode, the values given
for T2CON do not include the setting of the TR2 bit. There-
fore, bit TR2 must be set separately to turn the timer on.
TABLE
5-1: Timer/Counter 0
TMOD
Mode
0
Used as
Timer
1
2
3
0
Used as
Counter
1
2
3
Function
13-bit Timer
16-bit Timer
8-bit Auto-Reload
Two 8-bit Timers
13-bit Timer
16-bit Timer
8-bit Auto-Reload
Two 8-bit Timers
Internal
Control
1
00H
01H
02H
03H
04H
05H
06H
07H
External
Control
2
08H
09H
0AH
0BH
0CH
0DH
0EH
0FH
T5-1.0 1273
1. The Timer is turned ON/OFF by setting/clearing bit
TR1 in the software.
2. The Timer is turned ON/OFF by the 1 to 0 transition
on INT1# (P3.3) when TR1 = 1 (hardware control).
TABLE
5-3: Timer/Counter 2
T2CON
Mode
16-bit Auto-Reload
16-bit Capture
Internal
Control
1
00H
01H
34H
External
Control
2
08H
09H
36H
Used as
Timer
Baud rate generator
receive and transmit
same baud rate
Receive only
Transmit only
24H
14H
02H
03H
26H
16H
0AH
0BH
T5-3.0 1273
Used as
Counter
16-bit Auto-Reload
16-bit Capture
1. The Timer is turned ON/OFF by setting/clearing
bit TR0 in the software.
2. The Timer is turned ON/OFF by the 1 to 0 transition
on INT0# (P3.2) when TR0 = 1 (hardware control).
1. Capture/Reload occurs only on timer/counter overflow.
2. Capture/Reload occurs on timer/counter overflow and a 1
to 0 transition on T2EX (P1.1) pin except when Timer 2 is
used in the baud rate generating mode.
©2007 Silicon Storage Technology, Inc.
S71273-03-000
1/07
39
SST [ SILICON STORAGE TECHNOLOGY, INC ]
