Embedded Software for SoC - Grupo de Mecatrônica EESC/USP

Evaluation of Applying SpecC to the Integrated Design Method 147
As described in [7], the interface on the software side can be converted
mechanically. For the interface on the hardware side, mechanical conversion
is possible by preparing a bus interface circuit for bus models. By preparing
a channel library and an interface description for every channel included in
library, the mechanical conversion can be made more efficient. Since we were
able to show the mechanical conversion methods of SpecC description to softwares
and interface, we conclude that evaluation point (2) is satisfied.
6. CHANGE OF PARTITION POINT
The optimal partition point between a software and a hardware changes with
the demands and restrictions of a system. The advantage of the conversion
from integrated description is that the partition point of the device and the
device driver can be changed according to the need of the system. To be able
to change the partition point, a single behavior description should be
converted into both software and hardware.
To evaluate point (3) described in section 3, the partition point of the
software and the hardware is changed from a byte channel to a PPP packet
channel previous conversion. The difference between the byte channel conversion
and the PPP packet channel conversion is that the device that receives
the pointer has to take out the data from the memory using direct memory
access (DMA) because the PPP packet channel only passes the pointer to the
PPP packet.
6.1. Device driver and interface
For the SIO system, the objects of the device driver conversion are descriptions
of IP packet channels and PPP generation and analysis behaviors. As
described in section 5, the conversion can be done mechanically.
The PPP packet channels can be mechanically converted to an interface
using the method done with a byte channel. The functions of the channel for
PPP packet are equivalent to the functions of the byte channel. The only
difference is that in the conversion of PPP packet channels, the type
data_buffer is used so after the conversion the size of the device register
used to hold the a data_buffer is different from that of the byte channel.
6.2. Conversion of the device
This section describes the conversion of the byte channel and the byte transmit
behavior to the device. For description on the layer below the bit transmit/
receive behavior, conversion is the same as described in section 5. Since the
PPP packet channel transmits and receives pointers to PPP packet, the byte
transmit/receive behavior includes functions to access memory. To convert
memory access with pointers, the memory access is done using DMA. The