Connect One Ethernet shield

[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.