
1998 Oct 07
19
Philips Semiconductors
Product specification
Pager baseband controller
PCA5007
6.7
Timer/event counters
The PCA5007 contains two 16-bit timer/event counters,
Timer 0 and Timer 1, which can perform the following
functions:
Measure time intervals and pulse durations
Count events
Generate interrupt requests
Generate output on comparator match
Generate a Pulse Width Modulated (PWM) output
signal.
Timer 0 and Timer 1 can be programmed independently to
operate in four modes:
Mode 0: 8-bit timer or 8-bit counter each with
divide-by-32 prescaler
Mode 1: 16-bit time interval or event counter
Mode 2: 8-bit time interval or event counter with
automatic reload upon overflow
Mode 3: this mode of the standard 80C51 is not
available.
In the timer mode the timers count events on the XTL1
input. Timer 0 counts through a prescaler at a rate of
256 Hz and Timer 1 counts directly on both edges of the
XTL1 signal at a rate of 153.6 kHz. The nominal frequency
of the XTL1 signal is 76.8 kHz.
In the counter mode, the register is incremented in
response to a HIGH-to-LOW transition at P3.4 (T0) and
P3.5 (T1).
Besides the different input frequencies and the
non-availability of Mode 3, both Timer 0 and Timer 1
behave identically to the standard 80C51 Timer 0 and
Timer 1.
Fig.7 Timer/counter 0 and 1: clock sources and control logic.
Detailed configuration of the 4 available modes is found in the 80C51 family hardware description (“Philips Semiconductors IC20 Data Handbook”).
handbook, full pagewidth
MGR114
153.6 kHz
C/T = 0
C/T = 1
TL1
TH1
÷
300
256 Hz
C/T = 0
C/T = 1
TL0
XTL1
T0
TR0
Gate
INT0
XTL1
T1
TR1
Gate
INT1
TH0