Sundance SMT128 - Manual (Page 10)

Preliminary Page 10 of 15 SMT128 User Manual
Com Port Control
Four of the C6x com-ports connect to the DIN connector via a control CPLD. The
CPLD acts as a buffer for the Data com-port data lines. This allows multiple SMT128
to communicate in a system via the DSP’s com-ports. To allow the state of the com-
port to be reset, to their default states after a power-up condition, four registers
resources are provided. The table below shows the registers and their Global
address values.
Token Reset Control Registers
Com-Port Address Operations
Com 0 0xF0000000 Write 0x1 to reset the token for the com-
port then write a ‘0’
Com 1 0xF0000001 Write 0x1 to reset the token for the com-
port then write a ‘0’
Com 3 0xF0000002 Write 0x1 to reset the token for the com-
port then write a ‘0’
Com 4 0xF0000003 Write 0x1 to reset the token for the com-
port then write a ‘0’
Token Reset Software Functions and Method
On power-up the SMT128 com-port directions will be set to either Input or Output
depending on their com-port number. The CPLD buffers on the SMT128 will also be
reset to their correct state. When connecting multiple SMT128’s together in a system
there are situation when com-ports may become unsynchronised. To re-synchronise
the system it is necessary to do the following.
•
Reset the com-port in the DSP.
•
Reset the Com-port buffer on the SMT128.
To reset the DSP’s com-port register a write to the DSP’s com-port control register is
required (see SMT335 User Guide of details).
The Com-Port buffer on the SMT128 can be reset by writing a ‘1’ followed by a ‘0’ to
the corresponding com-port token Reset Control Register in the table above.