LTC6803-1/LTC6803-3
20
680313fa
OPERATION
Toggle Polling: Toggle polling allows a robust determina-
tion both of device states and of the integrity of the con-
nections between the devices in a stack. Toggle polling is
enabled when the LVLPL bit is low. After entering a polling
command, the data out line will be driven by the slave
devices based on their status. When polling for the ADC
converter status, data out will be low when any device is
busy performing an ADC conversion and will toggle at
1kHz when no device is busy. Similarly, when polling for
interrupt status, the output will be low when any device
has an interrupt condition and will toggle at 1kHz when
none has an interrupt condition.
Toggle Polling—Daisy-Chained Broadcast Polling: The
SDO pin (bottom device) or SDI pin (stacked devices) will
be low if a device is busy/in interrupt. If it is not busy/not
in interrupt, the device will pass the signal from the SDOI
input to data out (if not the top-of-stack device) or toggle
the data out line at 1kHz (if the top-of-stack device). The
master pulls CSBI high to exit polling.
Level Polling: Level polling is enabled when the LVLPL
bit is high. After entering a polling command, the data
out line will be driven by the slave devices based on their
status. When polling for the ADC converter status, data
out will be low when any device is busy performing an
ADC conversion and will be high when no device is busy.
Similarly, when polling for interrupt status, the output will
be low when any device has an interrupt condition and will
be high when none has an interrupt condition.
Level Polling—Daisy-Chained Broadcast Polling: The SDO
pin (bottom device) or SDI pin (stacked devices) will be
low if a device is busy/in interrupt. If it is not busy/not
in interrupt, the device will pass the level from the SDOI
input to data out (if not the top-of-stack device) or hold the
data out line high (if the top-of-stack device). Therefore,
if any device in the chain is busy or in interrupt, the SDO
signal at the bottom of the stack will be low. If all devices
are not busy/not in interrupt, the SDO signal at the bot-
tom of the stack will be high. The master pulls CSBI high
to exit polling.
CSBI
SCKI
SDI
SDO
MSB (CMD)
BIT6 (CMD) LSB (PEC)
TOGGLE OR LEVEL POLL
t
CYCLE
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Figure 6. Transmission Format (ADC Conversion and Poll)
CSBI
SCKI
SDI
SDO
MSB (CMD)
BIT6 (CMD) LSB (PEC)
TOGGLE OR LEVEL POLL
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Figure 7. Transmission Format (PLADC Conversion or PLINT)
