Rainbow Electronics MAX194 User Manual

Page 9

If you read the data bits between conversions, you can

1) count CLK cycles until the end of the conversion, or

2) poll EOC to determine when the conversion is

finished, or

3) generate an interrupt on EOC’s falling edge.

Note that the MSB conversion result appears at DOUT
after CS goes low but

before

the first SCLK pulse. Each

subsequent SCLK pulse shifts out the next conversion

bit. The 15th SCLK pulse shifts out the sub-LSB (S0).
Additional clock pulses shift out zeros.

Data is clocked out on SCLK’s falling edge. Clock data
in on SCLK’s rising edge or, for clock speeds above
2.5MHz, on the following falling edge to meet the maxi-
mum SCLK-to-DOUT timing specification (Figure 7).
The maximum SCLK speed is 5MHz. See the

Operating

Modes and SPI/QSPI Interfaces

section for additional

information. When the conversion clock is near its maxi-

MAX194

14-Bit, 85ksps ADC with 10µA Shutdown

_______________________________________________________________________________________

CLK

START

CONV

MAX194

CONV

START

CLK

SEE

DIGITAL INTERFACE SECTION

CONV

CLK

(CASE 1)

CLK

(CASE 2)

EOC

CEH

CASE 1: CLK IDLES LOW, DATA LATCHED ON RISING EDGE (CPOL = 0, CPHA = 0)
CASE 2: CLK IDLES LOW, DATA LATCHED ON FALLING EDGE (CPOL = 0, CPHA = 1)
NOTE: ARROWS ON CLK TRANSITIONS INDICATE LATCHING EDGE

CEL

DOUT

B13

CONVERSION

BEGINS

CONVERSION

ENDS

MSB

LSB

SUB-LSBs

B12

B11

B10

B13

B13 FROM PREVIOUS

CONVERSION

Figure 5. Gating CONV to Synchronize with CLK

Figure 6. Output Data Format, Reading Data During Conversion (Mode 1)