Datasheet

MCP23009/MCP23S09
DS22121B-page 12 © 2009 Microchip Technology Inc.
FIGURE 1-5: HARDWARE ADDRESS DECODE TIMING
1.4.2 ADDRESSING I
2
C DEVICES
(MCP23009)
The MCP23009 is a slave I
2
C device that supports 7-
bit slave addressing, with the read/write bit filling out
the control byte. The slave address contains four fixed
bits and three user-defined hardware address bits
(configured via ADDR pin). Figure 1-6 shows the
control byte format.
1.4.3 ADDRESSING SPI DEVICES
(MCP23S09)
The MCP23S09 is a slave SPI device. The slave
address contains seven fixed bits(no address bits) with
the read/write bit filling out the control byte. Figure 1-7
shows the control byte format.
FIGURE 1-6: I
2
C™ CONTROL BYTE
FORMAT
FIGURE 1-7: SPI CONTROL BYTE
FORMAT
VDD
adc_en
i2c_addr[2:0]
i2c_clk
t
ADEN
t
ADDRLAT
t
ADDIS
S 0 1 0 0 A2A1A0R/WACK
Start
bit
Slave Address
R/W bit
ACK bit
Control Byte
R/W = 0 = write
R/W = 1 = read
0100000R/W
Slave Address
R/W bit
Control Byte
R/W = 0 = write
R/W = 1 = read
CS