Analog Devices VisualDSP++ 5.0 Service Manual page 403

• Physical Drivers – Physical device drivers provide the functionality
necessary to control a physical device (for example, any configura-
tions register setting, device parameter setting, and so on). Physical
drivers are responsible for hooking into the error interrupts for
their device and processing them accordingly. If a device is not
supported by peripheral DMA, the physical driver must provide
the mechanism, a programmed I/O or the like, to move data
through the device.
• System Services – The device driver components rely heavily on
the functionality provided by the system services. For example, the
device manager relies on the interrupt manager and if required, the
DMA manager and deferred callback services. The functionality
provided by the system services is also available to physical drivers
to use. For example, a UART driver may need to know the
frequency in order to configure the UART to operate at a specific
baud rate. Through the power management service, the UART
physical driver can ascertain the current
Both the device driver model and system services are designed as portable
software components. They are mainly written in C, with some assembly
code in critical sections. As such, software that interacts with the device
driver model and system services must adhere to the C run-time model,
calling conventions, passing parameters, and so on. Applications and
physical drivers can be written in C or assembly. Wherever possible, there
are no dependencies on the code generation toolchain. System include
files are not required nor are the services of the toolchain's run-time librar-
ies. The device driver model and system services can be built and run
under any of the known code generation toolchains.
VisualDSP++ 5.0 Device Drivers and System
Services Manual for Blackfin Processors
Device Driver Manager
frequency.
SCLK
SCLK
10-5