The CS4231 is a 16 bit stereo codec chip with various features, such as multiple analog inputs and outputs, mixing, and gain capabilities, that make them ideal for computer sound applications. The digital interface consists of a parallel 8-bit bus and is meant to directly connect to a PC (ISA/EISA) interface. Since it is a glueless interface to a PC bus, it looks a bit different from a TMS320C5x or other TMS320 DSPs with asynchronous memory interface.
This Application Note describes an optimum interface to a TMS320C5x DSP. Note that other TMS320 DSP asynchronous buses are very similar and most of the interface described here will also apply to any TMS320 DSP system. In this implementation the TMS320C5x and codec share the same bus with SRAM. This tradeoff keeps pin count and thus cost down, at the cost of performance. A separate codec bus mapped into the DSP's memory or I/O space would make the system more efficient and is briefly described at the end of this Application Note along with other system considerations.