| Firmware:
Just Another Component |
 |
Coding
Approach and Methods |
| Historically,
at least half of all the
code written by Chelsfield
Consultants has been firmware. Our work covers
many types of programmable devices
from simple fusible gate arrays to
full custom ASIC's with
masked ROM built
around advanced DSP or MPU cores. |
|
| If
you contract us to assist
with your hardware design
project, then we would
strongly favor moving as
much system functionality
into the code domain as
possible. This becomes
especially important as
production volume increases
and one needs to minimise
future impact of updates to
both code and
hardware. In all cases
we would agree with you
which technology to apply
and the route to assembly of
the final binary
image. |
|
| You
may wish to contract us to
migrate your existing code
to a new device or
controller. If in this
case it's appropriate, we
will bring your engineering
in to the design loop and
provide complete project
transparency by working with
you to assist with the
specification, hardware
design, cross-assembly,
compilation and replication
of the final image,
documentation and
test. |
| |
| In
application specific situations where FPGA's
are used or where executable
code is contained in PROM
memory, the released version
of these devices may be treated as
just another component of
the production parts list.
It would be usual for you to
retain full IP and copyright in
these programs. |
|
|
 |
| If your project requires
it's glue logic placed in a
gate array there will be
little need to consult you
in depth once you have
agreed to this in
principle. Whereas for
larger projects we will
always ensure that we have a
common understanding with
you for each step in the
specification, design and
programming process. This
includes what tools, methods
and languages will be used. |
|
|
|
|
|
|
|
|
|
|
|
| Mass
Storage Selection |
|
Selection
of Processor |
| Devices
of current design in a wide
range of applications often
use mixed storage
technologies and techniques
for storing both operating systems,
applications and data.
Getting the mix right is
important and one should be
aware of the advantages and
limitations which each has
to offer. |
|
| The
performance specifications
from manufactures of flash
storage modules and sub
assemblies for example, are
all plausibly realistic.
However we have found that,
in numerous instances,
performance often falls short of
expectations. There may be
many reasons for this, but
operating outside standardised
test conditions even though
the device is working well
within the published
electrical specification,
can yield poor
results. Flash memory
devices used in bolt-on
modules can be rated
anywhere between 10,000 and
1,000,000+ write cycles. In
addition on board device
management, such as cell
write-cycle balancing,
varies greatly. |
|
| We
can assist you in the
selection and implementation
of storage devices and write
and assemble the RTS or core
code that runs
inside. |
|
|
| If you decide
to contract Chelsfield Consultants to
simply update existing firmware there
may be no need to alter the
configuration of the target hardware. In
cases where modifications are required
or for new projects we can formulate a
strategy for selecting the core
processor. In many instances a new
design can be built around a third party
SBC sub-assembly. There are a vast array
of these on the market covering a large number
of CPU cores. We have experience in
going down this design route and can
assist you to fit together core and I/O
sub-assemblies to match precise
requirements without compromising design
ideals. |
|
| Chelsfield
Solutions has worked with a wide
range of processors
including: 1802/4, 6502, 8041, 8048/9, 8051/251, 80522, 6800, 6804, 6809, 68HC11, Z80, 8080, 8085, x86, 8748/9, i960.
We are particularly experienced with the
following manufactures products: AMD,
Analogue
Devices, Burr-Brown,
Cypress,
Dallas
/ Maxim, Fairchild,
Fujitsu,
Harris
/ Intersil, Hitachi,
Intel, HP
/ Avago (Agilent), Mitel,
Mitsubishi,
Motorola,
National,
NEC,
Philips,
Samsung,
ST
Micro, Texas,
Toshiba,
Xilinx,
Zilog |
|
|
|
|
|
|
|
| Firmware:
Keeping
up to Date |
|
Robust
Logging
Applications |
 |
The
term firmware historically implied that OS code
was contained in a ROM device and that probably
it wouldn't change too often. Nowadays
however rapidly moving technology
necessitates the constant review of
functionality and this includes
embedded code. The need for constant
updating renders such software decidedly
less firm. Today
"firmware" may be loaded on
start up from any number of re-writable
mass storage media devices. One clear
advantage of this is to employ on-the-fly
update mechanisms.
Shown left is a Hydrostatic Stability
Monitor used on large marine vessels. This
was developed by Chelsfield on behalf of
University College London. The Unit OS may
be programmed directly by plugging EEproms
into the front panel.
|
|
|
| Chelsfield has
developed a number of robust logging applications
for a wide variety of applications in the pharmaceutical,
marine, aviation and security sectors,
amongst others. Very high
data rates, swamping noise and the need
for complex real-time transforms have all
been encountered. |
|
| One example is
the Digital Physiological Data Recorder (DPDR)
developed under commission from the
Defence Evaluation and Research Agency (DERA,
Formerly the Institute of Aviation
Medicine, (IAM)). |
|
|
|
|
|
The DPDR was designed
for use on the flight deck of a long
haul 747 to monitor physiological data
from the pilots. This demanding
application, which included
cardiac, neural, respiratory, ocular and
various motor functions, was delivered
on-time and on budget. |
|
|
