Datasheet

START
Opcode
(1)
S RTPinTA
DIN
t
DR
t
SETTLE
DRDY
STOP
Opcode
(1)
or
or
t
SDSU
t
DSHD
STOPOpcode
DRDY andDOUT
STARTPin
or
STOP
(1)
STOP
(1)
ADS1194, ADS1196
ADS1198
SBAS471C –APRIL 2010– REVISED NOVEMBER 2011 www.ti.com
Continuous Mode
Conversions begin when the START pin is taken high for at least two t
CLK
s or when the START opcode
command is sent. As seen in Figure 32, the DRDY output goes high when conversions are started and goes low
when data are ready. Conversions continue indefinitely until the START pin is taken low or the STOP opcode
command is transmitted. When the START pin is pulled low or the stop command is issued, the conversion in
progress is allowed to complete. Figure 33 and Table 8 show the required timing of DRDY to the START pin and
the START/STOP opcode commands when controlling conversions in this mode. To keep the converter running
continuously, the START pin can be permanently tied high. Note that when switching from pulse mode to
continuous mode, the START signal is pulsed or a STOP command must be issued followed by a START
command.
This conversion mode is ideal for applications that require a fixed continuous stream of conversion results.
(1) START and STOP opcode commands take effect on the seventh SCLK falling edge.
Figure 32. Continuous Conversion Mode
(1) START and STOP commands take effect on the seventh SCLK falling edge at the end of the opcode transmission.
Figure 33. START to DRDY Timing
Table 8. Timing Characteristics for Figure 33
(1)
SYMBOL DESCRIPTION MIN UNIT
START pin low or STOP opcode to DRDY setup time
t
SDSU
16 1/f
CLK
to halt further conversions
START pin low or STOP opcode to complete current
t
DSHD
16 1/f
CLK
conversion
(1) START and STOP commands take effect on the seventh SCLK falling edge at the end of the opcode transmission.
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