MCP23016-ISLASHSP datasheet(13/38 Pages) MICROCHIP

13 / 38 page

DS20090C-page 13

MCP23016

1.9.2

WRITING THE REGISTERS

To write to a MCP23016 register, the Master I2C device

needs to follow the requirements, as illustrated in

Figure 1-3. First, the device is selected by sending the

slave address and setting the R/W bit to logic ‘0’. The

command byte

sent

after

the

address

and

determines which register will be written. Table 1-3

shows the relationship of the command byte and

The MCP23016 has twelve 8-bit registers. They are

configured to operate as six 16-bit register pairs,

supporting the device’s 16-bit port. These pairs are

formed based on their functions (e.g., GP0 and GP1

are grouped together). The I2C commands apply to one

following a command byte is written into the register

pointed to by the command byte, while the second data

is written into another register in the same pair. For

example, if the first byte is sent to OLAT1 (command

byte 03h), the next data byte will be written into the sec-

ond register of that pair, OLAT0. If the first byte is writ-

ten to OLAT0 (command byte 02h), the second byte

will be written to OLAT1.

There is no limitation on the number of data bytes in

one write transmission. Figure 1-4 shows the case of

multiple byte writes in one write operation. In this case,

the multiple writes are made to the same data pair.

FIGURE 1-3:

WRITE TO CONFIGURATION

REGISTERS (CASE 1)

Note:

The bus must remain free until after the

ninth clock pulse for a minimum of 12 µs

(see Table 2-5 and Figure 2-4).

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