Programmable Wait States - Sundance Spas SMT335E User Manual

Version 3.0

Programmable Wait States

The SMT335E has its own internal software-configurable wait-state generator that is
used in conjunction with the external ready line, RDY. You control the generator by
configuring two fields in the Global Bus Control Register: WTCNT specifies the
number of software wait states to generate and SWW selects one of four options.
RDY is an internally generated ready signal. When an external access is begun,
wtcnt
the value WTCNT is loaded into a counter; WTCNT can be any value from 0 through
15. The counter is decremented every H1/H3 clock cycle until it becomes 0. Once the
counter reaches 0, it will remain at 0 until the next external access. RDY
while the counter is nonzero and 0 otherwise.
The four SWW options combine RDY and RDY
signal, RDY that controls accesses. As long as RDY
int
access is extended. When RDY
SWW = 00 RDY
2
SWW = 01 RDY
2
SWW = 10 RDY
2
SWW = 11 RDY
2
Additional information is available in the TMS320C4x User's Guide [5] chapter 9.4:
Programmable Wait States.
Note that bus sharing is supported in firmware versions 2.5 and above. The global
bus lines will be tri-stated according to the state of the AE, DE and CE lines.
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becomes 0, the current access will complete.
int
= RDY;
int
= RDY ;
int wtcnt
= RDY OR RDY;
int wtcnt
= RDY AND RDY; both must occur to generate ready.
int wtcnt
SMT335E SMT375E User Manual
to generate the internal ready
wtcnt
= 1, the current external
int
RDY is ignored.
wtcnt
RDY is ignored.
either generates ready.
will be 1
wtcnt