The header file <cyg/io/ccb_devio.h> defines the interface between the common CCB support and the target specific device drivers. The device drivers provide the physical CCB packet communication support.
Physical connections are supplied to the common layer via the relevant
target/platform defining a
structure (via the CCB_PORT() macro), which
provides the mapping to the relevant low-level hardware I/O driver via
the supplied named device.
cyg_ccb_devio_port_t structure defines a
hardware port instance (i.e. a physical RS-485 hardware interface)
driver in conjunction with a standard I/O driver device
descriptor DEVTAB_ENTRY() definition. A driver
normally instantiates itself via
the CCB_DEVIO_PORT() macro to populate
The device drivers interface with the CCB common layer via
cyg_ccb_callbacks_t structures implemented by
the src/ccb_devio.c support.
The device drivers fundamentally provide a per-port blocking transmit
function, and asynchronous packet reception. The driver calls back
into the common CCB layer via the (DSR