UM10147_2
© NXP B.V. 2008. All rights reserved.
User manual
Rev. 02 — 28 April 2008
52 of 134
NXP Semiconductors
UM10147
P89LPC952/954 User manual
8.6 Timer overflow toggle output
Timers 0 and 1 can be configured to automatically toggle a port output whenever a timer
overflow occurs. The same device pins that are used for the T0 and T1 count inputs and
PWM outputs are also used for the timer toggle outputs. This function is enabled by
Fig 17. Timer/counter 0 or 1 in Mode 2 (8-bit auto-reload).
002aaa921
PCLK
Tn pin
TRn
Gate
INTn pin
C/T = 0
C/T = 1
TLn
(8-bits)
THn
(8-bits)
TFn
control
ENTn
Tn pin
toggle
overflow
interrupt
reload
Fig 18. Timer/counter 0 Mode 3 (two 8-bit counters).
002aaa922
PCLK
Osc/2
T0 pin
TR0
TR1
Gate
INT0 pin
C/T = 0
C/T = 1
TL0
(8-bits)
TF0
control
ENT0
(AUXR1.4)
T0 pin
(P1.2 open drain)
toggle
overflow
interrupt
TH0
(8-bits)
TF1
control
ENT1
(AUXR1.5)
T1 pin
(P0.7)
toggle
overflow
interrupt
Fig 19. Timer/counter 0 or 1 in mode 6 (PWM auto-reload).
002aaa923
PCLK
TRn
Gate
INTn pin
C/T = 0
TLn
(8-bits)
THn
(8-bits)
TFn
control
ENTn
Tn pin
toggle
overflow
interrupt
reload THn on falling transition
and (256-THn) on rising transition