PT7C4372A Datasheet, PDF (24/30 Pages) Pericom Semiconductor Corporation – Real-time Clock Module

PT7C4372A/4372C
Real-time Clock Module (I²C Bus)
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Slave Address
The I²C bus device does not include a chip select pin such as is found in ordinary logic devices. Instead of using a chip select pin,
slave addresses are allocated to each device.
All communications begin with transmitting the [START condition] + [slave address (+ R/W specification)]. The receiving device
responds to this communication only when the specified slave address it has received matches its own slave address.
Slave addresses have a fixed length of 7 bits. This RTC's slave address is [ 0110 010 ].
An R/W bit ("*" above) is added to each 7-bit slave address during 8-bit transfers.
Table
Slave address
Transfer data
bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1
R / W bit
bit 0
Read
Write
65 h
1 (= Read)
0
1
1
0
0
1
0
64 h
0 (= Write)
I²C Bus’s Basic Transfer Format
S Start indication
P Stop indication
A RTC Acknowledge
Sr Restart indication
A Master Acknowledge
1) Write via I²C bus
S
Slave address (7 bits)
write ^A
01 1 0 01 0 0
Addr. setting
0h~Fh
Transfer mode _A bit bit bit bit bit bit bit bit _{A P}
0 1⁰ 0 0
76543210
Start
Slave address + write specification
A
A
C Address + transfer mode specification C Write data
K _{1) Specifies the write start address;}
K
2) Specifies the write mode (=0h fixed)
A Stop
C
K
12-07-0001
PT0150-8 07/04/12
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