ZT 88CT08A/88CT09A CMOS Boards
Addition of Optional 8087(-2)
As described in Chapter 7, "Numeric Data Processor," a special
module is available from Ziatech to allow addition of the 8087
Numeric Data Processor to the ZT 8808A and ZT 8809A. This
module, known as the zSBC 337,
normally comes with the
commercial 8087 or 8087-2 part mounted on the board. The "-2" part
is a faster part required for use with the ZT 8809A.
An extended temperature version of the 8087 Numeric Data
Coprocessor is also available from Ziatech.
This 8087 is
manufactured by Intel using a process that allows for operation within
the range of -40 to +85˚ C. A different part number is used to
distinguish this extended temperature part. Ziatech’s part number is
zSBC 337CT (the 8087-2 is used with the ZT 88CT09A). When
ordering the zSBC 337CT module with the ZT 88CT08A or
ZT 88CT09A, refer to the part as OPT 337CT.
Remember that this extended temperature 8087 is not a CMOS part,
and therefore not low power. It is designed for use by those systems
requiring CMOS for extended temperature operation and not low
power.
Clock Slowdown Mode
Power consumption for CMOS logic is directly proportional to the
device’s switching speed. The higher the clock frequency, the greater
the power dissipation. In order to minimize power consumption on
the ZT 88CT09A, a feature has been included to allow dynamic
switching of processor clock speed between normal frequency and
that frequency divided by 256. This is referred to as the Clock
Slowdown mode. The ZT 88CT08A may be selected to run at either
5 MHz or 19.5 kHz and the ZT 88CT09A at either 8 MHz or
31.25 kHz.
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