Application Interface - Analog Devices VisualDSP++ 5.0 Service Manual

• Device Manager – The device driver model is used to control
devices, both internal and external to Analog Devices processors.
Specific functionality allow the application to:
• Open and close devices used by the application.
• Configure and control devices.
• Receive and transmit data through the devices using a vari-
ety of dataflow methods.

Application Interface

Each system service exports an application programming interface (API)
that defines the interface into that service. Application software makes
calls into the API of the system service to access the functionality that is to
be controlled.
Each API can be called using the standard calling interface of the
development toolset's C run-time model. The API of each service can be
called by any C or assembly language program that adheres to the calling
conventions and register usage of the C run-time model.
In addition to the application software using the API to make calls into a
system service, some system services make calls into the API of other sys-
tem services. For the most part, each service is independent of the other
services; however, redundancies are eliminated by allowing one service to
access the functionality of another service.
For example, does the application need to be notified when a DMA
descriptor has completed processing, and the application has requested
deferred callbacks? In this case, the DMA management service invokes the
deferred callback service to effect the callback into the application.
Another example of combined operation between services involves the
power management and EBIU services. Assume that the system has
SDRAM and the application needs to conserve power by turning down
VisualDSP++ 5.0 Device Drivers and System
Services Manual for Blackfin Processors
Introduction
1-7