
MAX1112/MAX1113
+5V, Low-Power, Multi-Channel,
Serial 8-Bit ADCs
______________________________________________________________________________________
15
SCLK
DIN
DOUT
CS
S
CONTROL BYTE 0
CONTROL BYTE 1
S
CONVERSION RESULT 0
B7
B0
B7
B0
B7
CONVERSION RESULT 1
CONVERSION RESULT 2
SSTRB
CONTROL BYTE 2
S
1
888
10
1
10
1
10
1
CONTROL BYTE 3
S
Figure 12a. Continuous Conversions, External Clock Mode, 10 Clocks/Conversion Timing
CS
SCLK
DIN
DOUT
S
CONTROL BYTE 0
CONTROL BYTE 1
S
CONVERSION RESULT 0
B7
B0
B7
CONVERSION RESULT 1
Figure 12b. Continuous Conversions, External Clock Mode, 16 Clocks/Conversion Timing
Data Framing
The falling edge of CS does not start a conversion. The
first logic high clocked into DIN is interpreted as a start
bit and defines the first bit of the control byte. A conver-
sion starts on the falling edge of SCLK, after the eighth
bit of the control byte (the PD0 bit) is clocked into DIN.
The start bit is defined as:
The first high bit clocked into DIN with CS low any
time the converter is idle, e.g., after VDD is applied.
OR
The first high bit clocked into DIN after the MSB of a
conversion in progress is clocked onto the DOUT
pin.
If CS is toggled before the current conversion is com-
plete, then the next high bit clocked into DIN is recog-
nized as a start bit; the current conversion is
terminated, and a new one is started.
The fastest the MAX1112/MAX1113 can run is 10
clocks per conversion. Figure 12a shows the serial-
interface timing necessary to perform a conversion
every 10 SCLK cycles in external clock mode.
Many microcontrollers require that conversions occur in
multiples of eight SCLK clocks; 16 clocks per conver-
sion is typically the fastest that a microcontroller can
drive the MAX1112/MAX1113. Figure 12b shows the
serial-interface timing necessary to perform a conver-
sion every 16 SCLK cycles in external clock mode.