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)
ADS1294, ADS1294R
ADS1296, ADS1296R
ADS1298, ADS1298R
www.ti.com SBAS459I –JANUARY 2010–REVISED JANUARY 2012
Continuous Mode
Conversions begin when the START pin is taken high for at least 2 t
CLK
s or when the START opcode command
is sent. As seen in Figure 41, 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 42 and Table 10 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 conversions
results.
(1) START and STOP opcode commands take effect on the seventh SCLK falling edge.
Figure 41. Continuous Conversion Mode
(1) START and STOP commands take effect on the seventh SCLK falling edge at the end of the opcode transmission.
Figure 42. START to DRDY Timing
Table 10. Timing Characteristics for Figure 42
(1)
SYMBOL DESCRIPTION MIN UNIT
START pin low or STOP opcode to DRDY setup time
t
SDSU
16 t
CLK
to halt further conversions
START pin low or STOP opcode to complete current
t
DSHD
16 t
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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