bigger eval board than DEMO9S08QG8?

[irob]

Hey everybody. I've loved my Axiom DEMO9S08QG8 demo board. Only problem I have right now is I'm running out of I/O for some bigger projects.

I've looked at the softecmicro PK-HCS08GB60 starter kit. It's also USB, has a row of LEDs, an analog pot, but only one user switch. But there doesn't appear to be a BDM out port to program target parts.

It's based on the MC9S08GB60, so it has four 8-bit ports.

Any other suggestions for a bigger, better demo board?

[Jaux]

Hi Rob,

Due to the same restrictions I have developed my own prototyping board based on the AW60 chip.

Every I/O pin is mapped to the edge connectors and you can optionally switch in the two serial ports via a MAX232, switch in a RS-485 controller and switch in optional driving devices to power and drive a standard LCD module.

You can use almost any xtal - from 32Khz or prefably 9.8304Mhz or even 20Mhz

The BDM connecter is edge-wired seperately

It has an embedded 1A switching supply which can take 9 - 20 VAC input in a "power-over-RS-485" configuration.

Board size is 70 x 95 mm

You are welcome to the design, PCB Gerbers etc.

Let me know

John

[bigmac]

Hello John,

---

Jaux wrote:

It has an embedded 1A switching supply which can take 9 - 20 VAC input in a "power-over-RS-485" configuration.

---

I would be interested to find out a little more about the details of your "power over RS485" concept.  Thanks in advance.

Regards,
Mac

[Jaux]

Mac,

OK - basically what I am doing is using a 4-core screened cable for the multi-drop.

2 + screen is used in RS-485 communication and two wires cary the AC which get regulated, smoothed and switch-regulated to 5 or 3.3V. I have used the 12V lighting transformers with success.

If you need more detail - let me know and I will do a little app-note style technical document.

BR, John

[bigmac]

Hello John,

For  a moment, I thought you might have been distributing power over the same pair as the communications, or using some sort of common mode arrangement - but realize this is probably not possible for RS485.  I have previously used spare pairs on Cat. 5 cable for the purpose of distributing low current DC power, in some cases from a standby battery and battery charger combination.  I presume your use of a switching regulator gives much wider voltage compiance than a linear regulator, and with lower dissipation - be it for somewhat higher cost.

I am currently updating the design of my RS485 based equipment, and propose to use an isolated RS485 interface to eliminate earth loops for the wiring to the slave equipment, in a multi-drop master/slave system.  To supply power to the isolated side of the interface, I seem to have the choice of using an isolated DC-DC converter supplied from the non-isolated side (expensive?), or to remotely supply the DC power from the common master location.  For the latter alternative, it would be hard to justify the use of a switching regulator at each slave.

This was why I was interested in your post.  Incidently, I am also thinking of upgrading to the AW32 device (in the 44-pin package) for this project, assuming I can actually get hold of the silicon here (in Australia) - not always possible in more moderate quantities.

Regards,

Mac

Message Edited by bigmac on 2007-01-1611:02 AM

[Jaux]

Mac,

Just round the corner from me ( Cape Town, South Africa) - nice see somebody from down South.

I have tried to contrust an arrangement using the data pairs for conveying the AC, but the problem is that in oder to get any reasonable distance on RS-485 one has to watch the baud-rate and even using 115 kB, the seperation from 50 Hz is tricky, and the isolation transformer is bulky, expensive and does not work very well. So the 4-core screened cable is pretty standard what we use for normal RS-232 comms. Also, the 4-Cs cable is cheaper than CAT-5 cable.

I am using a LM2575T (~ USD1.2 ea )( switching regulator soldered directly to a copper-pour area on the PCB. See attached pic. I agree it is a little expensive, but this arrangement take away all headaches of a typlical noisy industrial deployment. Using this arrangement will eliminate your earth-loop problems.

I love the AW60 and AW32 chip - We have standardized on this for all our 8-bit applications. Try asking Freescale for samples if you need one or two for prototyping, or you can buy small quantities directly from Freescale ( shipping however is expensive )

dsc00119.jpg

Message Edited by t.dowe on 2009-09-22 12:00 PM

[joerg]

Hi Rob
since i hate the usual demo boards i have developed the HC(S)08 system. The idea is to have a "mainboard" and different modules for your MPU as well as a lot of "addons" to get started with your prototype. I wanted to include a simple OS witch has become my EBS08 as a base for the software (i am using Motorola/freescale MPU for about 20 years now) having a lot of modules beside. Then for every hardware module i have also the schematics as a module, so once i have finished the software and having tested it i do the layout based on my modules. All this save a lot of time and is kind of foolproof! (at least i do the mistakes normally only once!).
For more infos visit www.systech-gmbh.ch -> HC(S)08 system for the hardware and -> EBS08 for the software. If you need help ask here or send a mail to info@systech-gmbh.ch

Saluti Joerg

[irob]

John, thanks for the kind offer. I sent you a private message.

Joerg, your site has quite a wealth of information. I love your module-based approach to the Freescale MCUs. Very cool. Thanks for the help, everyone!

[OldMan]

You can unplug the QG8 chip form the DEMO9S08QG8 and use it as a USB-BDM tool. I used that for a BT16A chip that I wired myself. Works greate. The switches, LEDs, photo-detector, etc. on the DEMO9S08QG8 can be used too.

[irob]

OldMan, you are right about the QG8 demo board. It's very nice in that there is the BDM port available. That's what I've been using primarily, but recently ran out of I/O.

Encoder, where can I buy an AW60 demo board? That thing sound great!

[Encoder]

Depending where you are, you may easily buy it from DigiKey in USA or from Farnell or RS-components in Europe: all they usually have it in stock and you may have it in a couple of days as I did. The price may slightly vary.

But many other classic distributors like Avnet or Arrow have it. And you may order it also from Freescale Direct Buy Service for 84.99$, but I do not know if its is available in stock.

Informations, electric diagrams, guides and everything are completely available on this Freescale site.

Encoder

[Encoder]

Hi Irob. I think that you hardly will actually find a better demo board than DEMO9S08AW60 for the same price for the 9S08 family.

It has a lot of I/O on board and many leds and pushbuttons to experiment with other than 2 RS232 and USB BDM. Not to talk of the expensive 64 pin QFP socket which would cost you more than the whole board if bought as a spare part and which is invaluable to permit to replace a possibly blown cpu (unfortunately I found the AW60 quite delicate on the ESD side).

Yes, the accelerometer is completely unusefull but the potentiometer and the light sensor may be good. I have at least 6 or 7 HC08xx demo board but I abandoned all them for DEMO9S08AW60 which permits you to work either on 3 or 5V supply environment and, most af all has BDM interface.

Regards,

Encoder