Hello David,
i use 1 Aduc812 for master and for 2 Aduc812 for slave.
The master must tell both the slaves "start the measurement", That's all.

Possibilities:
1: I can use SPI by UART, but dont know how to realize that with ADuc812.
2: I can use D/A out to give pulse from master to slave, but slave must get this pulse by int0 (p3.2)

Maybe no. 2 should be faster. But how to realize to get this pulse by int0 (p3.2) for slave in c code?

Thanks
Walter