configuration, apm, init, dataframe, error
General Description: When configuring an FPGA in the
Asynchronous Peripheral Mode (APM) by decoding an mcs format
promfile with a microprocessor, INIT drives Low.
This can be caused by an unexpected indexing line in the middle
of the file. When decoding prom files for FPGA configuration,
the prom addressing data must be removed. This consists of 8
ascii hexidecimal characters, preceeded by a colon (:), on each
line in the file, and an indexing line. See example below:
The first line is an indexing line in the mcs format. The
addressing for each index begins at 10000 Hex. When 10FFF Hex
is reached in the address section, a new index is inserted.
See example below:
If an mcs file is created for more than 557056 configuration
bits, then multiple index lines will be used. Not stripping
these out will cause them to be decoded and sent to the FPGA as
configuration data, and thus will cause a dataframe error which
is flagged by driving INIT low.