I am planning to use the SPORTs of the ADSP-21489 to communicate with an external ADC and a DAC in a relatively high speed data acquisition chain, and I need some help to estimate the delay associated with the serial communication.
The ADC and the DAC work with 16 bits words at a throughput rate of 1 MS/s (only one channel). A serial clock at 18 to 40 MHz will be used (probably 40 MHz). The SHARC core clock will be set to 400 MHz.
Which processing delay can I expect from input to output, supposing that the only processing taking place in the DSP is two bi-quad IIR filters?
Can i estimate the communication delay as 16 x 1/40MHz = 400 ns for the input (and the same for the output), or are there auxiliary buffers or other time-consuming elements in the SPORT routines adding extra delay to data transfer?