Philips Semiconductors
Product data
P87C51RA2/RB2/RC2/RD2
80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP
with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high
speed (30/33 MHz)
2003 Jan 24
14
INTn Pin
Timer n
Gate bit
TRn
TLn
(5 Bits)
THn
(8 Bits)
TFn
Interrupt
Control
C/T = 0
C/T = 1
SU01618
OSC
÷ d*
Tn Pin
*d = 6 in 6-clock mode; d = 12 in 12-clock mode.
Figure 3. Timer/Counter 0/1 Mode 0: 13-Bit Timer/Counter
IT0
BIT
SYMBOL
FUNCTION
TCON.7
TF1
Timer 1 overflow flag. Set by hardware on Timer/Counter overflow.
Cleared by hardware when processor vectors to interrupt routine, or clearing the bit in software.
TCON.6
TR1
Timer 1 Run control bit. Set/cleared by software to turn Timer/Counter on/off.
TCON.5
TF0
Timer 0 overflow flag. Set by hardware on Timer/Counter overflow.
Cleared by hardware when processor vectors to interrupt routine, or by clearing the bit in software.
TCON.4
TR0
Timer 0 Run control bit. Set/cleared by software to turn Timer/Counter on/off.
TCON.3
IE1
Interrupt 1 Edge flag. Set by hardware when external interrupt edge detected.
Cleared when interrupt processed.
TCON.2
IT1
Interrupt 1 type control bit. Set/cleared by software to specify falling edge/low level triggered
external interrupts.
TCON.1
IE0
Interrupt 0 Edge flag. Set by hardware when external interrupt edge detected.
Cleared when interrupt processed.
TCON.0
IT0
Interrupt 0 Type control bit. Set/cleared by software to specify falling edge/low level
triggered external interrupts.
SU01516
IE0
IT1
IE1
TR0
TF0
TR1
TF1
Bit Addressable
TCON
Address = 88H
Reset Value = 00H
76
54
321
0
Figure 4. Timer/Counter 0/1 Control (TCON) Register