Sundance SMT335E - Manual (Page 14)

Version 1.5 Page 14 of 53 SMT335E SMT375E User Manual
Communication ports
Overview
The SMT335E provides six 8-bit, data-parallel, inter-processor links that follow Texas
Instruments’ TMS320C4x Communication Port standard. Additional information on
the standard is available in the TMS320C4x User’s Guide chapter 12:
Communication ports and the Texas Instrument Module Specification
.
The standard gives a TIM six links numbered from 0 to 5. Each link can be a
transmitter or a receiver, and will switch automatically between these states
depending on the way you use it. Writing to a receiver or reading from a transmitter
will cause a hardware negotiation (token exchange) that will reverse the state of both
ends of the link.
Following a processor reset, the first three links (0, 1, and 2) initialise as transmitters
and the remainder (3, 4, and 5) initialise as receivers. When you wire TIMs together
you must make sure that you only ever connect links initialising as transmitters to
links initialising as receivers; never connect two transmitters or two receivers. For
example, connecting link 0 of one TIM to link 4 of another is safe; connecting link 0 of
one TIM to link 2 of another could damage the hardware.
Always connect comm-ports 0, 1, or 2 to comm-ports 3, 4, or 5.
On the SMT320 carrier board the physical connection between comm-ports is made
with FMS cables (Ref. SMT3xx-FMS). You must be careful when connecting the
cables the make sure that one end is inserted in the opposite sense to the other. One
end must have the blue backing facing out and the other must have the silver
backing facing out.
The SMT320 motherboard communicates with the host PC using comm-port 3 of the
site 1 TIM. You should not make any other connections to this comm-port.