ISPPAC81 Datasheet, PDF (19/20 Pages) Lattice Semiconductor – In-System Programmable Analog Circuit

Lattice Semiconductor
ispPAC81 Data Sheet
and BBE are used to return all user bits to a zero state at the same time. An ABE or BBE usually proceeds a PRGA
or PRGB operation, otherwise one to zero changes would not be implemented. It can also be used to erase all con-
figuration information from a device and is the default condition of parts shipped from the factory. The same pro-
gramming time constraints apply to ABE and BBE as for PRGA and PRGB. The bit code for this instruction is
shown in Table 5.
The ADDUSR, BYPASS, EXTEST, IDCODE and SAMPLE/PRELOAD instructions are all executed in the Update-
IR state. Other instructions: PRGUSR, VERUSR and UBE are executed upon entry of the Run-Test/Idle state.
It is recommended that when all serial interface operations are completed, the TAP controller be reset and left in
the Test-Logic-Reset state (the power-up default) and the TCK and TMS inputs idled. This will insure the best ana-
log performance possible by minimizing the effects of digital logic “feed-through.”
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