c8051t617 Silicon Laboratories, c8051t617 Datasheet - Page 173

• Manufacturer Part Number: c8051t617
• Description: Mixed Signal Byte-programmable Eprom Mcu
• Manufacturer: Silicon Laboratories

18.1.4. Mode 3: Two 8-bit Counter/Timers (Timer 0 Only)
In Mode 3, Timer 0 is configured as two separate 8-bit counter/timers held in TL0 and TH0. The coun-
ter/timer in TL0 is controlled using the Timer 0 control/status bits in TCON and TMOD: TR0, C/T0, GATE0
and TF0. TL0 can use either the system clock or an external input signal as its timebase. The TH0 register
is restricted to a timer function sourced by the system clock or prescaled clock. TH0 is enabled using the
Timer 1 run control bit TR1. TH0 sets the Timer 1 overflow flag TF1 on overflow and thus controls the
Timer 1 interrupt.
Timer 1 is inactive in Mode 3. When Timer 0 is operating in Mode 3, Timer 1 can be operated in Modes 0,
1 or 2, but cannot be clocked by external signals nor set the TF1 flag and generate an interrupt. However,
the Timer 1 overflow can be used to generate baud rates for the SMBus and/or UART, and/or initiate ADC
conversions. While Timer 0 is operating in Mode 3, Timer 1 run control is handled through its mode set-
tings. To run Timer 1 while Timer 0 is in Mode 3, set the Timer 1 Mode as 0, 1, or 2. To disable Timer 1,
configure it for Mode 3.
/INT0
T0
Crossbar
Pre-scaled Clock
SYSCLK
IN0PL
GATE0
Figure 18.3. T0 Mode 3 Block Diagram
XOR
0
1
TR0
M
T
3
H
M
T
3
L
CKCON
M
H
T
2
0
1
M
T
2
L
M
T
1
M
T
0
S
C
A
1
S
C
A
0
Rev. 0.3
TR1
G
A
T
E
1
C
T
1
/
M
T
1
1
TMOD
C8051T610/1/2/3/4/5/6/7
M
T
1
0
G
A
T
E
0
C
T
0
/
M
T
0
1
M
T
0
0
(8 bits)
(8 bits)
TH0
TL0
TR1
TR0
TF1
TF0
IE1
IE0
IT1
IT0
Interrupt
Interrupt
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