PCA88021 NXP [NXP Semiconductors], PCA88021 Datasheet - Page 5

• Manufacturer Part Number: PCA88021
• Description: ultra low power oscillator with integrated counter for initiating one time password generation
• Manufacturer: NXP [NXP Semiconductors]

NXP Semiconductors
9. Functional description
PCA8802_1
Product data sheet
9.1.1 Power-on
9.1 Oscillator
The PCA8802 is an ultra low power device for battery operations. The integrated oscillator
circuit generates a
between the PCA8802 and other devices is made via an I
The device is always running but for longer storage time it can be switched off and on
again in case of delivery.
The functions of the device can be controlled with the following instruction set:
Table 4.
The 32.768 kHz oscillator includes two integrated load capacitors and an automatic gain
control to ensure a reliable start-up.
For prototype development and system debugging, it is possible to output a 32.768 kHz
square wave on the INT pin with the 32k_cmd instruction.
At initial power-on, when the oscillator has not yet started, a reset will be generated.
During this state the serial interface will not respond when accessed. To ensure that the
oscillator has started and the serial interface is accessible, it is recommended that the
master attempts to make write-read accesses to the counter register.
Instruction
wrt_cmd
dvs_cmd
pwd_cmd
32k_cmd
fst_cmd
set_cmd
rd_cmd
Fig 5.
oscillation
Exit from Power-down mode will give the same behavior as start-up.
Power-on reset
V
Instruction set overview
DD
Description
device write access
divider start or stop switch
low power mode switch
32.768 kHz clock signal on the pin INT switch
fast system development mode switch
set counter instruction
counter read instruction
1
32
Rev. 01 — 19 February 2009
instructions will be ignored
Hz clock signal to increment a 24 bit counter. The communication
oscillation now stable
instructions will be accepted
2
C-bus.
PCA8802
Reference
Section 9.6.2
Section 9.6.3
Section 9.6.4
Section 9.6.5
Section 9.6.6
Section 9.6.7
Section 9.6.8
© NXP B.V. 2009. All rights reserved.
Smartcard RTC
001aaj166
t
5 of 34