Redpine Signals has assembled a kit that can help engineers and
product designers include a Wi-Fi port in a product, and thus connect wireless
equipment to other networked devices or the Internet. I found the kit easy to
use and it quickly detected and connected to a wireless router. Testing would
have taken less time, but the lack of clear instructions caused a delay. I
would give this kit higher marks but for several warnings noted below.
Instead of designing its own kit, Redpine collaborated with
Renesas to create a small Wi-Fi board that plugs into a Renesas RSKR8C25
Starter Kit (provided). The latter kit includes a microcontroller board, character
LCD, emulator pod, software and a power supply. The separate Redpine board
supplies an RS9110-N-11-22 wireless-device server module that complies with the
IEEE 802.11/b/g/n specifications. The small module can operate with open or secure
Wi-Fi access points and it supplies its own wireless LAN stack. Software on the
Renesas MCU board communicates with the Redpine board through either a serial
port or with an SPI port. In an OEM product, you would buy RS9110-N-11-22
modules and communicate with them from your own MCU using an AT-like command
set.
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Because the kit came with a printed Renesas Quick-Start Guide
(QSG) and CD but only a Redpine CD, I started with the Renesas information and
installed the company's High-performance Embedded Workshop (HEW) tools. After
working through the Renesas instructions, LEDs on the MCU board flashed and a
test message appeared on the LCD. So far, so good.
Next I examined the Redpine CD and printed its readme.txt file
that list the CD's contents: demo software, manuals, RS9110-N-11-22 module
information and code, and another copy of the Renesas HEW tools. A Redpine
Quick-Start Guide explains how to attach the Wi-Fi board to the MCU board and
then conduct an auto-connect test with a wireless router. I ran into two
problems. First, the test required an open (unsecured) wireless access point,
so I had to remove security from my lab network, which I disliked doing, but it
seemed impractical to carry the boards, power supply and laptop PC to the local
pizza place where they have open Wi-Fi access.
Second - and worse - by building and loading the Renesas LED/LCD
test program I had wiped out Redpine's pre-programmed firmware in the Renesas
MCU. So, the plug-it-in-and-try-it "experience" stopped temporarily. The
Redpine QSG included information about a Manual Mode engineers can use to
modify some network information in the original firmware and load the new
firmware into the Renesas MCU. I followed the instructions but
did not change the code and then loaded
the firmware into the MCU. That step restored the Redpine firmware and the
combined Redpine/Renesas boards detected my wireless router and provided an IP
address. A Java program on the Redpine CD ran on my wireless laptop and let me
control LEDs on the Renesas board via a wireless connection.
The first paragraph in the Manual Mode instructions notes kit
users should only go through steps 1 through 16 in the Renesas QSG so they
won't overwrite the Redpine firmware. Good advice, but too late. Redpine should
include this information on colored paper and mark it boldly "Start
Here" or others will have the same problem I did, which wasted a lot of
time. That's my first warning.
After you turn LEDs on or off from a computer on your network
you'll want to investigate other things you can do with the Renesas/Redpine kit.
The Redpine "API Library for Renesas Microcontrollers" manual
explains how to use the Redpine application programming interface (API)
operations for UART-to-module or SPI-to module communications and it includes C
source code for three such programs. The source code starts out simple enough
until you realize it pulls in many other files. The tcp_udp_app.c file, for
example, includes almost no code comments, and comment templates at the start
of functions lack function names and descriptions. So, wading through the code
to try to understand it could become a time sink. That's my second warning.
Although Redpine notes its modules respond to an AT-like command
set, I found no documentation for such commands. The supplied API seems to
apply only - at least so far - to Renesas MCUs. A close look at the AT command
might give developers insight into how easy or difficult it might be to use the
Wi-Fi modules with non-Renesas MCUs. (I await instructions from the Redpine
support people about where to find the AT-command-set information.)
I bet Redpine hopes engineers will buy its chips and modules so
they can get "on the air" quickly with Wi-Fi communications. But,
without details about how to set up specific operations, what the various
commands do, and how to use parameters, creating code for the Redpine products
will require a long climb up a steep learning curve. At the least, Redpine
should provide a basic skeleton communication program, a flow chart, an explanation
of parameters, and even a check list of things to include in a basic program.
Let's hope Redpine can give engineers this information soon. That's my last
warning.
So although the kit worked well and performed as advertised, it
might not take engineers all the way to a complete Wi-Fi-based application.
Click
here
for information about the RS9110-N-11-22 wireless-device server module.
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