Connect One Ethernet shield

[mackrackit]

uhmm,
I need to quit falling asleep. I missed the part about volunteering..

I do not have a whole lot of time to dedicate to a new project as much as I want too. But I will try to find some time to play

As far as EEPROMs... FRAM seems kind of expensive. Not sure how big of one would be needed, maybe a 24FC1025 would be "OK" ? After it is all setup should be just READS....

Need to sleep on it some more

[dhouston]

As far as EEPROMs...

I already have board designs for a battery backed RTC and for an EEPROM. Both are I2C and they might be plugins on shields that should require one or the other. I use 64KB in another application so it would be simplest to just use it, as is. Or, it might be best to just provide for a DIP that the user could add.

I'm also kicking around my own design for a slightly more costly but much easier and much more powerful Arduino clone that would make a great test bed and development system It's all this time on my idle hands...

[dhouston]

I think I can forget about seeing the Tibbo firmware anytime soon so here is what I think is the final layout for the ConnectOne ethernet shield. The TX, RX connections are dictated by the PICAXE and Xino. I still need to check this with the Xino designer but I think it's ready to have CircuitMart make some prototype PCBs.



When the Tibbo firmware is released I hope someone will consult a medium and let me know.

I'm going to spend my time finalizing the design of yet another Arduino clone. This will use a ZBasic ZX328n but it will be socketed so it can be replaced with a AVR Mega328P.

When my Xino kit arrives I'll see whether it is practical to modify to use the comparators as inverters for TX, RX. That should work with 16F88, 16F886/887 and 18P25K20/22, lowering the chip count.

[mister_e]

When the Tibbo firmware is released I hope someone will consult a medium and let me know.

Ask your supplier to let you know

[mackrackit]

I must have missed something ..
Where/when did a picaxe come in and why???

[dhouston]

I must have missed something ..
Where/when did a picaxe come in and why???

Sleeping again, huh?

The Xino basic Arduino form factor main board was designed to be a super low cost way for educators to make use of the myriad of shields available. It can use 18-pin or 28-pin PICAXE or PIC. I have a kit en route and hope to modify it to add series resistors in the TX, RX lines so that the comparators in the 16F88, 16F886/887 & 18F25K20/22 can be configured as inverters for TX, RX further reducing the parts count. There are pinouts for both 18-pin and 28-pin PICAXE chips at the above link.

I am not really familiar with PICAXE but it appears the software UART pins are predefined so that's why I connected them per the pinouts. Also, the newer PICAXE 18M2 and 28X2 chips are custom made by Microchip for PICAXE. I have no idea whether this just means they have their logo printed on them or whether there are changes to the designs. I haven't seen datasheets for them. But, if they can justify custom chips from Microchip, PICAXE must be very popular.

Since all the PBP software UART pins can be defined at compile time by the user, this should not be problem for PBP users.

And, I still have to study the pinouts to see where the I2C connections need to be made. I2C presents one problem in that there's no way to easily deal with address conflicts should another shield also use I2C. I'll probably just tie all the address pins high with the leads exposed in such a way that the user can cut PCB traces to change the address. Also, multiple pull-ups could be problematic

Also, I already have small I2C boards with 64KB EEPROM (SMT) which could be an optional item. I also have a similar board with a battery-backed RTC which uses the same pinout . But, I don't want to become a supplier (My next change of address may make me inaccessible.) so I'll have to see if the Xino folks will make them. Still, it might be best just to design for a DIP-8 socket and through-hole pull-ups.

[dhouston]

I just noticed that the Xino Pro, which uses the same pin arrangements, has a pinout for the 18F25K20 on its web page. That should help in determining which PICs are compatible.