MCP4441 datasheet(56/100 Pages) MICROCHIP

56 / 100 page

MCP444X/446X

DS22265A-page 56

6.2.4

ADDRESSING

The address byte is the first byte received following the

START condition from the master device. The address

contains four (or more) fixed bits and (up to) three user

defined hardware address bits (pins A1 and A0). These

7-bits address the desired I2C device. The A6:A2

address bits are fixed to “01011” and the device

appends the value of following two address pins (A1

and A0).

Since there are address bits controlled by hardware

pins, there may be up to four MCP44XX devices on the

same I2C bus.

Figure 6-9 shows the slave address byte format, which

contains the seven address bits. There is also a read/

write (R/W) bit. Table 6-2 shows the fixed address for

device.

Hardware Address Pins

The hardware address bits (A1, and A0) correspond to

the logic level on the associated address pins. This

allows up to eight devices on the bus.

These pins have a weak pull-up enabled when the VDD

< VBOR. The weak pull-up utilizes the “smart” pull-up

technology and exhibits the same characteristics as the

High-voltage tolerant I/O structure.

The state of the A0 address pin is latch on POR/BOR.

This is required since High Voltage commands force

this pin (HVC/A0) to the VIHH level.

FIGURE 6-9:

Slave Address Bits in the

I2C Control Byte.

TABLE 6-2:

DEVICE SLAVE ADDRESSES

6.2.5

SLOPE CONTROL

The MCP44XX implements slope control on the SDA

output.

As the device transitions from HS mode to FS mode,

the slope control parameter will change from the HS

specification to the FS specification.

For Fast (FS) and High-Speed (HS) modes, the device

has a spike suppression and a Schmidt trigger at SDA

and SCL inputs.

Device

Address

Comment

MCP44XX ‘0101 1’b + A1:A0

Supports up to 4

devices. (Note 1)

Note 1:

A0 is used for High-Voltage commands

(HVC/A0) and the value is latched at

POR/BOR.

S A6A5 A4 A3A2 A1 A0 R/W

A/A

Start

bit

Slave Address

R/W bit

A bit (controlled by slave device)

R/W

= 0 = write

R/W

= 1 = read

= 0 = Slave Device Acknowledges byte

= 1 = Slave Device does not Acknowledge byte

“0” “1” “0” “1”

See Table 6-2

“1”

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