gbadev.org forum archive

This is a read-only mirror of the content originally found on forum.gbadev.org (now offline), salvaged from Wayback machine copies. A new forum can be found here.

DS development > slot 2 serial interface?

#114351 - scknight - Sun Jan 07, 2007 1:51 am

Now that we're starting to get more slot 1 devices it seems to me that this really opens up more possibilities for homebrew option paks. I was trying to find out some more information about using slot 2 as a serial connection to external devices. I tried searching the boards and various wikis and I could only really find info about using the SPI with slot 1. So could anyone point me in the right direction to finding out more information about using the gba slot for interfacing with devices. Thanks

#114352 - KeithE - Sun Jan 07, 2007 2:08 am

You can "misuse" each line of the slot 2 parallel interface as a serial interface by doing a sequence of reads from specific SRAM addresses.

There is a slow enough rise time on the SRAM address lines that this will work. I have used this method to create a SPI interface from four of the parallel lines.

#114366 - scknight - Sun Jan 07, 2007 4:18 am

Any examples of pins your using and code to do the serial access?