MCP4431 Microchip Technology Inc., MCP4431 Datasheet - Page 48

• Manufacturer Part Number: MCP4431
• Description: 7/8-bit Volatile Quad Digital Pot With I 2c Interface
• Manufacturer: Microchip Technology Inc.

MCP443X/5X
6.2
The MCP44XX’s I
NXP I
modules features:
• 7-bit slave addressing
• Supports three clock rate modes:
• Support Multi-Master Applications
• General call addressing
• Internal weak pull-ups on interface signals
The I
The NXP I
field lengths, timings, etc. of a frame. The frame con-
tent defines the behavior of the device. The frame con-
tent for the MCP44XX is defined in Section 7.0.
6.2.1
Figure 6-8
clock is generated by the master. The following defini-
tions are used for the bit states:
• Start bit (S)
• Data bit
• Acknowledge (A) bit (driven low) /
• Repeated Start bit (Sr)
• Stop bit (P)
6.2.1.1
The Start bit (see
a data transfer sequence. The Start bit is defined as the
SDA signal falling when the SCL signal is “High”.
FIGURE 6-2:
6.2.1.2
The SDA signal may change state while the SCL signal
is Low. While the SCL signal is High, the SDA signal
MUST be stable (see
FIGURE 6-3:
DS22267A-page 48
SDA
SCL
SDA
SCL
- Standard mode, clock rates up to 100 kHz
- Fast mode, clock rates up to 400 kHz
- High-speed mode (HS mode), clock rates up
No Acknowledge (A) bit (not driven low)
to 3.4 MHz
2
2
C 10-bit addressing mode is not supported.
C specification. The following lists some of the
I
2
2
S
shows the I
C Operation
C specification only defines the field types,
I
2
C BIT STATES AND SEQUENCE
Start Bit
Data Bit
Figure
2
C module is compatible with the
Figure
2
Start Bit.
Data Bit.
C transfer sequence. The serial
6-2) indicates the beginning of
1st Bit
6-5).
Data Bit
1st Bit
2nd Bit
2nd Bit
6.2.1.3
The A bit (see
the receiving device to the transmitting device.
Depending on the context of the transfer sequence, the
A bit may indicate different things. Typically the Slave
device will supply an A response after the Start bit and
8 “data” bits have been received. an A bit has the SDA
signal low.
FIGURE 6-4:
Not A (A) Response
The A bit has the SDA signal high.
some of the conditions where the Slave Device will
issue a Not A (A).
If an error condition occurs (such as an A instead of A),
then an START bit must be issued to reset the
command state machine.
TABLE 6-1:
General Call
Slave Address
valid
Slave Address
not valid
Device Memory
Address and
specified
command
(AD3:AD0 and
C1:C0) are an
invalid
combination
Communica-
tion during
EEPROM write
cycle
Bus Collision
SDA
SCL
Event
Acknowledge (A) Bit
Figure
8
D0
MCP45XX/MCP46XX A / A
RESPONSES
Acknowledge
Bit Response
6-4) is typically a response from
Acknowledge Waveform.
N.A.
 2010 Microchip Technology Inc.
A
A
A
A
A
Only if GCEN bit is
set
After device has
received address
and command
After device has
received address
and command,
and valid
conditions for
EEPROM write
I
Resets, or a “Don’t
Care” if the
collision occurs on
the Master’s “Start
bit”
2
C Module
Table 6-1
Comment
9
A
shows