Book Analog Interfacing to Embedded Microprocessors
must be considered as well as the throughput of the processor. If there are
multiple devices on the SPI bus, then you have to be sure the bus can support
the total throughput required of all the devices. Of course, the processor has
to keep up with the overall data rate as well.
40 Analog Interfacing to Embedded Microprocessors
Multichannel ADCs
Many ADCs are available with multiple channels—anywhere from 2 to 8. The
Analog Devices AD7824 is a typical device, with 8 channels. The AD7824
contains a single 8-bit ADC and an 8-channel analog multiplexer. The micro-
processor interface to the AD7824 is similar to the Maxim MAX151, but with
the addition of three address lines (A0–A2) to select which channel is to be
converted. Like the MAX151, the AD7824 may be used in a mode where the
microprocessor starts a conversion and is placed into a wait state until the con-
version is complete
annaabi.ee 
