MAX6956 データシートの表示（PDF） - Maxim Integrated

部品番号

コンポーネント説明

メーカー

MAX6956

2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or 28-Port LED Display Driver and I/O Expander

Maxim Integrated 

2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or

28-Port LED Display Driver and I/O Expander

START CONDITION

SCL

1

2

SDA

BY TRANSMITTER

CLOCK PULSE FOR ACKNOWLEDGMENT

8

9

S

SDA

BY RECEIVER

Figure 5. Acknowledge

SDA

1

0

MSB

SCL

0

A3

A2

A1

A0

R/W

ACK

LSB

Figure 6. Slave Address

MAX6956 is the recipient. When the MAX6956 is trans-

mitting to the master, the master generates the

acknowledge bit because the master is the recipient.

Slave Address

The MAX6956 has a 7-bit-long slave address (Figure 6).

The eighth bit following the 7-bit slave address is the

R/ W bit. It is low for a write command, high for a read

command.

The first 3 bits (MSBs) of the MAX6956 slave address

are always 100. Slave address bits A3, A2, A1, and A0

are selected by address inputs, AD1 and AD0. These

two input pins may be connected to GND, V+, SDA, or

SCL. The MAX6956 has 16 possible slave addresses

(Table 3) and therefore, a maximum of 16 MAX6956

devices may share the same interface.

Message Format for Writing

the MAX6956

A write to the MAX6956 comprises the transmission of

the MAX6956’s slave address with the R/ W bit set to

zero, followed by at least 1 byte of information. The first

byte of information is the command byte. The com-

mand byte determines which register of the MAX6956

is to be written by the next byte, if received. If a STOP

condition is detected after the command byte is

received, then the MAX6956 takes no further action

(Figure 8) beyond storing the command byte.

Any bytes received after the command byte are data

bytes. The first data byte goes into the internal register of

the MAX6956 selected by the command byte (Figure 9). If

multiple data bytes are transmitted before a STOP condi-

tion is detected, these bytes are generally stored in subse-

quent MAX6956 internal registers because the command

byte address generally autoincrements (Table 4).

Message Format for Reading

The MAX6956 is read using the MAX6956’s internally

stored command byte as address pointer, the same

way the stored command byte is used as address

pointer for a write. The pointer generally autoincre-

ments after each data byte is read using the same rules

as for a write (Table 4). Thus, a read is initiated by first

configuring the MAX6956’s command byte by perform-

_______________________________________________________________________________________ 9

Share Link: