SPI interface schematic

[rpalmer]

Hello People,

I have been busy with HDOS implementing extended long name support. It now support the reading of MS DOS long filenames upto 60 characters (enough for now).

But now I have learned more about Eagle to draw up schematics, so no I have converted the original SPI interface which was in an Excel spreadsheet using very crude picture elements to a schematic in eagle format.

I have also been able create a PCB layout, but for now I am in the process of desk checking the schematic to make sure it works as expected.
The interface has two SPI "ports" so that various devices can be implemented (it can be expanded to four for more capability).

The SPI interface is at 5V, but the micro SD card interface converts this 3.3V, so in theory any SPI interface device such as the ENC28J60 (ethernet) can also be connected without much fuss. The documentation for this chip has the required details for such a connection.

Attached is the schematic in a PDF, but once checked to work as expected I will put here the full schematic in all its glory.

Two devices which be attached is an SD card interface I found on the internet (see https://www.sparkfun.com/products/13743, I have also attached the image of the item).

Once the version with the Micro SD works, I can make that version (including the attached micro SD interface) for those who want it and include a free micro SD card (say 8Gb as they are now cheap as chips...LOL).

rplamer

[freemac]

You need also a controller (implementing protocol in hard way to simplify interaction),  if you want to plug eth or sdcard.
But for some "led ribbon", or plugging some others Arduino gadget it can do the stuff, like that perhaps :
* http://www.robot-electronics.co.uk/htm/usb_iss_tech.htm (controller integrated)
* http://www.robot-electronics.co.uk/htm/usb_iss_spi_tech.htm
Fun with SPI is that you can plug several peripherals.

[rpalmer]

freemac,

The addition of a MCU like an atmega32 is possible (and has been done before), but all it does is implement a TCP/IP stack and API.

I have done this before (TCP/IP and API) for the CS8900a chip, so the ENC28J60 should be that much of a step. If this become too much then yes I can implement something like an atmega MCU to do the workload.

rpalmer

[TotO]

You can already do that by using the MiniBooster. Just plug your module over its expansion pins.