Microchip Technology MCP3422EV Data Sheet
MCP3422/3/4
DS22088C-page 22
© 2009 Microchip Technology Inc.
5.3.4
READING OUTPUT CODES AND
CONFIGURATION BYTE FROM THE
DEVICE
CONFIGURATION BYTE FROM THE
DEVICE
When the Master sends a read command (R/W = 1),
the device outputs both the conversion data and
configuration bytes. Each byte consists of 8 bits with
one acknowledge (ACK) bit. The ACK bit after the
address byte is issued by the device and the ACK bits
after each conversion data bytes are issued by the
Master.
the device outputs both the conversion data and
configuration bytes. Each byte consists of 8 bits with
one acknowledge (ACK) bit. The ACK bit after the
address byte is issued by the device and the ACK bits
after each conversion data bytes are issued by the
Master.
When the device is configured for 18-bit conversion
mode, it outputs three data bytes followed by a
configuration byte. The first 6 data bits in the first data
byte are repeated MSB (= sign bit) of the conversion
data. The user can ignore the first 6 data bits, and take
the 7th data bit (D17) as the MSB of the conversion
data. The LSB of the 3rd data byte is the LSB of the
conversion data (D0).
mode, it outputs three data bytes followed by a
configuration byte. The first 6 data bits in the first data
byte are repeated MSB (= sign bit) of the conversion
data. The user can ignore the first 6 data bits, and take
the 7th data bit (D17) as the MSB of the conversion
data. The LSB of the 3rd data byte is the LSB of the
conversion data (D0).
If the device is configured for 12, 14, or 16 bit-mode, the
device outputs two data bytes followed by a
configuration byte. In 16 bit-conversion mode, the MSB
(= sign bit) of the first data byte is D15. In 14-bit
conversion mode, the first two bits in the first data byte
are repeated MSB bits and can be ignored, and the 3rd
bit (D13) is the MSB (=sign bit) of the conversion data.
In 12-bit conversion mode, the first four bits are
repeated MSB bits and can be ignored. The 5th bit
(D11) of the byte represents the MSB (= sign bit) of the
conversion data.
device outputs two data bytes followed by a
configuration byte. In 16 bit-conversion mode, the MSB
(= sign bit) of the first data byte is D15. In 14-bit
conversion mode, the first two bits in the first data byte
are repeated MSB bits and can be ignored, and the 3rd
bit (D13) is the MSB (=sign bit) of the conversion data.
In 12-bit conversion mode, the first four bits are
repeated MSB bits and can be ignored. The 5th bit
(D11) of the byte represents the MSB (= sign bit) of the
conversion data.
summarizes the conversion
data output of each conversion mode.
The configuration byte follows the output data bytes.
The device repeatedly outputs the configuration byte
only if the Master sends clocks repeatedly after the
data bytes.
The device repeatedly outputs the configuration byte
only if the Master sends clocks repeatedly after the
data bytes.
The device terminates the current outputs when it
receives a Not-Acknowledge (NAK), a repeated start or
a stop bit at any time during the output bit stream. It is
not required to read the configuration byte. However,
the Master may read the configuration byte to check
the RDY bit condition.The Master may continuously
send clock (SCL) to repeatedly read the configuration
byte (to check the RDY bit status).
receives a Not-Acknowledge (NAK), a repeated start or
a stop bit at any time during the output bit stream. It is
not required to read the configuration byte. However,
the Master may read the configuration byte to check
the RDY bit condition.The Master may continuously
send clock (SCL) to repeatedly read the configuration
byte (to check the RDY bit status).
show the timing diagrams of the
reading.
TABLE 5-3:
OUTPUT CODES OF EACH RESOLUTION OPTION
Conversion
Option
Digital Output Codes
18-bits
MMMMMMD17D16 (1st data byte) - D15 ~ D8 (2nd data byte) - D7 ~ D0 (3rd data byte) - Configuration
byte. (Note 1)
byte. (Note 1)
16-bits
D15 ~ D8 (1st data byte) - D7 ~ D0 (2nd data byte) - Configuration byte. (Note 2)
14-bits
MMD13D ~ D8 (1st data byte) - D7 ~ D0 (2nd data byte) - Configuration byte. (Note 3)
12-bits
MMMMD11 ~ D8 (1st data byte) - D7 ~ D0 (2nd data byte) - Configuration byte. (Note 4)
Note 1:
D17 is MSB (= sign bit), M is repeated MSB of the data byte.
2:
D15 is MSB (= sign bit).
3:
D13 is MSB (= sign bit), M is repeated MSB of the data byte.
4:
D11 is MSB (= sign bit), M is repeated MSB of the data byte.