1997 Dec 12 3
Philips Semiconductors Product specification
32 kHz watch circuits with EEPROM PCA16xx series
PINNING
SYMBOL PIN DESCRIPTION
V
SS
1 ground (0 V)
TEST 2 test output
OSC IN 3 oscillator input
OSC OUT 4 oscillator output
V
DD
5 positive supply voltage
M1 6 motor 1 output
M2 7 motor 2 output
RESET 8 reset input
Fig.1 Pin configuration, PCA16xxT, (PMFP8).
1
2
3
4
8
7
6
5
PCA16xxT
V
SS
TEST
OSC IN
OSC OUT
RESET
M2
M1
V
DD
MSA973
FUNCTIONAL DESCRIPTION AND TESTING
Motor pulse
The motor pulse width (t
P
) and the cycle times (tT) are
given in Chapter “Available types”.
Voltage level detector
The supply voltage is compared with the internal voltage
reference V
LIT
and V
EOL
every minute. The first voltage
level detection is carried out 30 ms after a RESET.
Lithium mode
If a lithium voltage is detected (V
DD
≥ V
LIT
), the circuit will
operate in the lithium mode. The motor pulse will be
produced with a 75% duty factor.
Silver-oxide mode
If the voltage level detected is between V
LIT
and V
EOL
, the
circuit will operate in silver-oxide mode.
Battery end-of-life
(1)
If the battery end-of-life is detected (VDD≤ V
EOL
), the
motor pulse will be produced without chopping. To indicate
this condition, bursts of 4 pulses are produced every 4 s.
Power-on reset
For correct operation of the Power-on reset the rise time of
V
DD
from 0 V to 2.1 V should be less than 0.1 ms.
All resettable flip-flops are reset. Additionally the polarity of
the first motor pulse is positive: VM1− VM2≥ 0V.
(1) Only available for types with a 1 s motor pulse.
Customer testing
An output frequency of 32 Hz is provided at RESET (pin 8)
to be used for exact frequency measurement. Every
minute a jitter occurs as a result of time calibration, which
occurs 90 to 150 ms after disconnecting the RESET from
VDD.
Connecting the RESET to VDD stops the motor pulses
leaving them in a HIGH impedance 3-state condition and a
32 Hz signal without jitter is produced at the TEST pin.
A debounce circuit protects accidental stoppages due to
mechanical shock to the watch (t
DEB
= 14.7 to 123.2 ms).
Connecting RESET to VSS activates Tests 1 and 2 and
disables the time calibration.
Test 1, VDD>V
EOL
. Normal function takes place except
the voltage detection cycle (tV) is 125 ms and the cycle
time tT1 is 31.25 ms. At pin TEST a minute signal is
available at 8192 times its normal frequency.
Test 2
(2)
, VDD<V
EOL
. The voltage detection cycle (tV) is
31.25 ms and the motor pulse period (tT2) = 31.25 ms.
Test and reset mode are terminated by disconnecting the
RESET pin.
Test 3, VDD> 5.1 V. Motor pulses with a time period of
tT3= 31.25 ms and n × 122 µs are produced to check the
contents of the EEPROM. At pin TEST the motor pulse
period signal (tT) is available at 1024 times its normal
frequency. The circuit returns to normal operation when
VDD< 2.5 V between two motor pulses.
(2) Only applicable for types with the battery end-of-life detector.