S-7750C Datasheet, PDF (10/44 Pages) Seiko Instruments Inc – PROGRAMMABLE PORT CONTROLLER (PORT EXPANDER WITH BUILT-IN E2PROM CIRCUIT)

PROGRAMMABLE PORT CONTROLLER (PORT EXPANDER WITH BUILT-IN E²PROM CIRCUIT)
S-7750C
Rev.1.1_00
„ Device Addressing
To start communication, the master device (MPU) on the system generates a start condition for the slave device
(S-7750C). After that, the master device sends a device address with 7-bit and Read / Write instruction code with 1-bit
on the SDA bus. The higher 3 bits in a device address (DC2, DC1, DC0) are device codes. The fixed value which users
selected by option (either one of 000, 001, 010, 011, 100, 101, 110, 111) is a device code. Command is omitted if a
device code does not correspond. The next 1-bit TA / C is a bit for timer address setting / command switch.
When TA / C = “1”, the next 3 bits (C2, C1, C0) are used as address, when TA / C = “0”, (C2, C1, C0) are used as
command for the timer setting register.
Start
Condition
Timer address setting /
command switch
Device
Code
Address /
command
Acknowledgment
Read / Write bit ^Signal
STA DC2 DC1 DC0 TA / C C2
C1
MSB
Register data
C0 R / W ACK
Stop
LSB
Condition
B7
B6
B5
B4
B3
B2
B1
B0 ACK STP
MSB
LSB
Figure 10 Device Addressing
10
Seiko Instruments Inc.