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9120A–AUTO–01/08
ATA6831/ATA6832 Driver ICs
6.2
Parallel Operation of Several ATA6831s
In applications with a high number of loads, parallel operation of the ATA6831 via the microcon-
troller is possible.
Chip select pins CS1 to CS4 each provides an independent means of controlling the ATA6831’s
serial peripheral interface. (For a functional description of the serial peripheral interface, please
refer to the datasheet.)
For simultaneous operation of the serial peripheral interfaces (i.e., CS1 through CS4 active at
the same time), each of the data outputs (DO) needs to communicate with a dedicated micro-
controller input pin.
Figure 6-2.
Parallel Operation with Microcontroller and Watchdog
6.3
Daisy Chaining of Several ATA6831s
Daisy chaining is a second option available to connect several ATA6831s to the microcontroller
for applications with a high number of loads. A daisy chain arrangement requires only one CS
line. The data signal is handed over step-by-step from one ATA6831 to the next as long as CS
signal stays low. The use of only one CS link, however, results in slower reaction times, as sev-
eral programming cycles are needed to load the desired setting into each ATA6831.
The DI pin of the first IC acts as input for all ICs, and the DO of the last IC represents the output
for the whole chain. The dataword intended for the last IC has to be put in first, followed by the
word for the IC before and so on. In contrast to other ICs of the Atmel driver family, only a total of
n shifts are needed for n ICs as any DI information is transferred immediately to the output
register.
V
CC
V
CC
Reset
T
ri
gger
Enable
CS1
CLK
DO
DI
INH
ATA6831
ATA6831
ATA6831
CS
CLK
DO
DI
CS
CLK
DO
DI
CS
CLK
DO
DI
INH
INH
INH
CS2
CS3
CS4
CS
CLK
DO
DI
ATA6831
U5021M
WATCHDOG
Micro-
controller
