Rainbow Electronics T89C51AC2 - Manual (Page 62)

62
T89C51AC2
Rev. B – 19-Dec-01
13.3 Registers Table 26. T2CON Register
T2CON (S:C8h)
Timer 2 Control Register
Reset Value = 0000 0000b
Bit addressable
7 6 5 4 3 2 1 0
TF2 EXF2 RCLK TCLK EXEN2 TR2 C/T2# CP/RL2#
Bit
Number
Bit
Mnemonic Description
7 TF2
Timer 2 overflow Flag
TF2 is not set if RCLK=1 or TCLK = 1.
Must be cleared by software.
Set by hardware on timer 2 overflow.
6 EXF2
Timer 2 External Flag
Set when a capture or a reload is caused by a negative transition on T2EX pin if
EXEN2=1.
Set to cause the CPU to vector to timer 2 interrupt routine when timer 2 interrupt
is enabled.
Must be cleared by software.
5 RCLK
Receive Clock bit
Clear to use timer 1 overflow as receive clock for serial port in mode 1 or 3.
Set to use timer 2 overflow as receive clock for serial port in mode 1 or 3.
4 TCLK
Transmit Clock bit
Clear to use timer 1 overflow as transmit clock for serial port in mode 1 or 3.
Set to use timer 2 overflow as transmit clock for serial port in mode 1 or 3.
3 EXEN2
Timer 2 External Enable bit
Clear to ignore events on T2EX pin for timer 2 operation.
Set to cause a capture or reload when a negative transition on T2EX pin is
detected, if timer 2 is not used to clock the serial port.
2 TR2
Timer 2 Run control bit
Clear to turn off timer 2.
Set to turn on timer 2.
1 C/T2#
Timer/Counter 2 select bit
Clear for timer operation (input from internal clock system: F
OSC
).
Set for counter operation (input from T2 input pin).
0 CP/RL2#
Timer 2 Capture/Reload bit
If RCLK=1 or TCLK=1, CP/RL2# is ignored and timer is forced to auto-reload on
timer 2 overflow.
Clear to auto-reload on timer 2 overflows or negative transitions on T2EX pin if
EXEN2=1.
Set to capture on negative transitions on T2EX pin if EXEN2=1.