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active High, without any additional logic. The VLTN signal is used for both Command
and Data violations. Buffering of the DSTRB and VLTN signals may be necessary as
illustrated in Figure 15 to meet the drive requirements of the first column of registers.
Da t a /Co m m a n d Ou t p u t No t e :
In this system, when a nonSync Command byte is received the data line values
corresponding to that byte will change to the values last output from the TAXI Receiver
data lines. Conversely, when a data byte is received the command line values for that
byte will change to the values last output from the TAXI Receiver command lines. This is
a characteristic of the example given and depends on how the command and data
information is latched.
Alt e rin g t h e Nu m b e r o f Ou t p u t Byt e s :
The above described design is an example of a four byte cascaded serial data receiving
system. The same design techniques can be used to expand or reduce the number of
bytes output at a time by the system. The considerations that should be taken into
account for an altered system deal with board space and part cost in accordance with
the requirements of the situation at hand. For board space note see the PAL Usage
section below.
P AL Us a g e :
In this system, the use of a PAL could greatly reduce the amount of board space used.
The PAL could incorporate all of the flip-flops and buffering logic as well as the first
column of registers that capture the system information. The reason a PAL was not
used in the system described above was to help ensure the understanding of the design
concept. For this application it is recommended that the timing considerations men-
tioned before should be investigated to ensure proper operation of the system.
TAXIchip Integrated Circuits Technical Manual
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