MAX11644 Datasheet, PDF (13/21 Pages) Maxim Integrated Products – 2.7V to 3.6V and 4.5V to 5.5V, Low-Power, 1-/2-Channel, 2-Wire Serial, 12-Bit ADCs

2.7V to 3.6V and 4.5V to 5.5V, Low-Power,
1-/2-Channel, 2-Wire Serial, 12-Bit ADCs
Configuration/Setup Bytes (Write Cycle)
A write cycle begins with the bus master issuing a
START condition followed by seven address bits
(Figure 7) and a write bit (R/W = 0). If the address byte
is successfully received, the MAX11644/MAX11645
(slave) issues an acknowledge. The master then writes
to the slave. The slave recognizes the received byte as
the set-up byte (Table 1) if the most significant bit
(MSB) is 1. If the MSB is 0, the slave recognizes that
byte as the configuration byte (Table 2). The master
can write either one or two bytes to the slave in any
order (setup byte, then configuration byte; configura-
tion byte, then setup byte; setup byte or configuration
byte only; Figure 9). If the slave receives a byte suc-
cessfully, it issues an acknowledge. The master ends
the write cycle by issuing a STOP condition or a repeat-
ed START condition. When operating in HS mode, a
STOP condition returns the bus into F/S mode (see the
HS Mode section).
MASTER TO SLAVE
SLAVE TO MASTER
A) ONE-BYTE WRITE CYCLE
1
7
11
8
11
S
SLAVE ADDRESS
WA
SETUP OR
CONFIGURATION BYTE
A
P OR Sr
NUMBER OF BITS
MSB DETERMINES WHETHER
SETUP OR CONFIGURATION BYTE
B) TWO-BYTE WRITE CYCLE
1
7
11
8
1
8
11
S
SLAVE ADDRESS
WA
SETUP OR
CONFIGURATION BYTE
A
SETUP OR
CONFIGURATION BYTE
A P OR Sr
NUMBER OF BITS
MSB DETERMINES WHETHER
SETUP OR CONFIGURATION BYTE
Figure 9. Write Cycle
Table 1. Setup Byte Format
BIT 7
(MSB)
REG
BIT 6
SEL2
BIT 5
SEL1
BIT 4
SEL0
BIT 3
CLK
BIT 2
BIP/UNI
BIT 1
RST
BIT 0
(LSB)
X
BIT
NAME
DESCRIPTION
7
REG
Register bit. 1 = setup byte, 0 = configuration byte (Table 2).
6
SEL2
5
SEL1
Three bits select the reference voltage (Table 6).
Default to 000 at power-up.
4
SEL0
3
CLK
1 = external clock, 0 = internal clock. Defaults to 0 at power-up.
2
BIP/UNI 1 = bipolar, 0 = unipolar. Defaults to 0 at power-up (see the Unipolar/Bipolar section).
1
RST
1 = no action, 0 = resets the configuration register to default. Setup register remains unchanged.
0
X
Don’t-care bit. This bit can be set to 1 or 0.
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