%% Direct Memory Access (DMA) Parameters
% DMAEXCL
This parameter controls a software lock that restricts
the four-channel DMA controller to exercise one channel
at a time, that is, not to use its capability to perform
transfers on separate channels simultaneously.  This was 
a software solution to problems with early production runs 
of the chips.  Setting the value to 1 avoids 
simultaneous use of the channels within a single chip.
Setting the value to 2 avoids simultaneous use of 
all channels for all chips.
