pca8802 NXP Semiconductors, pca8802 Datasheet - Page 14

• Manufacturer Part Number: pca8802
• Description: Smartcard Rtc; Ultra Low Power Oscillator With Integrated Counter For Initiating One Time Password Generation
• Manufacturer: NXP Semiconductors

NXP Semiconductors
Table 5.
The writing protocol is illustrated in
PCA8802_1
Product data sheet
First byte
Instruction Instruction code Instruction Instruction code Parameters
wrt_cmd
Write instructions
1010 0000
9.6.1 Instruction set
9.6.2 Instruction wrt_cmd
9.6.3 Instruction dvs_cmd
9.6 Instructions
Table 6.
The reading protocol is illustrated in
[1]
The write instruction (wrt_cmd) precedes each write sequence. Details of the writing
protocol can be found in
The divider switch instruction (dvs_cmd) can be used to freeze the divider chain and to
put it in a defined state. The first two bits of the divider chain can not be influenced. With
this instruction it is possible to control the time to the next increment of the counter. See
Table
First byte
Instruction Instruction code Parameters
rd_cmd
Read of the counter is implicit with an interface read.
8.
Second byte
dvs_cmd
pwd_cmd
32k_cmd
fst_cmd
set_cmd
[1]
Figure
Read instructions
1010 0001
10.
0001 0001
0001 0000
0010 0001
0010 0000
0011 0001
0011 0000
0100 0001
0100 0000
1000 0000
Rev. 01 — 19 February 2009
Section
Further bytes Action
P1[23:16]
P2[15:8]
P3[7:0]
P4[23:16]
:
Figure
9.5.1.1.
Further bytes Action
-
-
-
-
-
-
-
-
-
P1[23:16]
P2[15:8]
P3[7:0]
11.
device slave read address: slave address plus
read bit
parameter with counter values;
continues to read until no ACK is received;
counter is not updated during this time
device slave write address: slave address
plus write bit
stop and reset dividers
start dividers
shut down the device
enable the device
enable output of 32.768 kHz on pin INT
disable output of 32.768 kHz on pin INT
fast mode; increments counter every
second
fast mode disable
set the counter value
parameter with counter values
PCA8802
© NXP B.V. 2009. All rights reserved.
Smartcard RTC
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