User Manual

7521/2/2A/3/4/7 Series Hardware User’s Manual, Ver. 1.5 Sep/2002, 7Mh-001-15 -----4
The 7521 series modules have been very successful during the past three
years. Over one hundred thousand modules have been shipped to locations all
over the world. The reasons for our success are given as follows:
 Time-to-market & cost-effective solutions
 Durable, stable, flexible, & easy to program
 Over 50 various I/O modules are supported
 Can be used in harsh, noisy industry environments
However, even though the 7521 series is so versatile, there are some
applications that cannot be initially solved, such as:
 High speed applications
 Special hardware requirement applications
 Special software requirement applications
 A combinations of special hardware & software applications
Therefore, we developed an I/O expansion bus for the 7521 series to solve
all the above applications above. The I/O expansion bus can be used to
implement various I/O functions such as D/I, D/O, A/D, D/A, Timer/Counter,
UART, flash memory, battery backup SRAM, AsicKey & other I/O functions.
Nearly all kinds of I/O functions can be implemented by this bus.
The I/O expansion bus includes serial & parallel interface. The parallel
interface is very similar to ISA bus, so the user can move the old ISA bus
design to the I/O expansion bus with very little modification.
Furthermore, the I/O pins of the serial bus are programmable. They can be
programmed as D/I, or D/O. Some pins can be configured to D/I or D/O or
timer input or timer output. There are many serial interface devices today. The
features of these serial devices are given as follows:
 Smaller size compared to parallel devices
 Lower cost compared to parallel devices
 Easier to design for isolation applications