Eccp Instruction Timing; Reseteccp Instruction; Updatemlse Instruction With Soft Decision - Lucent Technologies DSP1617 Information Manual

Information Manual DSP1611/17/18/27/28/29 DIGITAL SIGNAL PROCESSOR
April 1998 Error Correction Coprocessor (DSP1618/28 Only)

14.6 ECCP Instruction Timing

ECCP Data Move Timing: Each ECCP data move instruction takes two cycles.
Viterbi Instruction Timing: Following are formulas defining the number of instruction cycles for six different cate-
gories of ECCP processes. The number of instruction cycles is measured from the time when the eir register is
written with the ECCP command to the time when the output data is ready in the edr register.

14.6.1 ResetECCP Instruction

The ResetECCP instruction has no latency.

14.6.2 UpdateMLSE Instruction with Soft Decision

The generic formula for the computation of the UpdateMLSE instruction cycles with soft decision (i.e., SH = 0) is as
follows:
( ) ( )
CL + 2 CL + 2 CL
( )Cycles Max 0 [ TBLR 2 ]
UpdateMLSE SH = 0 = 15 + 2 + , + 2 4
– –
where CL represents the value of the constraint length field in the ECON register and TBLR is the traceback length
value programmed into the TBLR register.
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