Alpha 3 is out

I'm proud to announce Alpha 3 release of ZPUino.

As usual, you can find it in http://www.alvie.com/zpuino/

Here are the release notes:

Programmer/bootloader

* Programmer now uses a dual-speed transfer. It starts at 115200 baud for identification, then ramps up speed if required.
* Some bugfixes and refactoring.
* Preliminary direct memory upload. Still untested.

Core

* New main ZPU core: ZPU Premium. You should expect almost a 3x performance increase, when compared with old core.
* New PPS implementation. Things should have become clearer now. See more information on PPS page
* IO selection is now clearer, so to ease adding new devices. See Implementing or porting IO devices document for more information
* Fixed RAM indexing, which caused synthesis warnings

Boards

* Added per-board SPI clock dividers for bootloader

Spartan 3E Evaluation Board

* First prebuilt image for this board
* Design was not being properly built, fixed that.
* Changed clock speed to 96MHz, instead of 100MHz. This helps meeting timing and give accurate baud rate dividers
* Fixed GPIO mappings
* Added proper IO pads

Documentation

* Added IO device tutorial: Implementing or porting IO devices
* Added Advanced IO: Advanced IO
* Added PPS documentation for users: Peripheral Pin Select

Known Issues

* There is still no Win32 port. Some dificculties arose so I'm delaying to next release. But good news is that compiler is now built, but other parts of the toolchain still need some tweaking, as well as the IDE set up.
* Resetting the serial port sometimes fails when using a real RS232 cable. This is probably due to ringing - I'll address this on next release (this only affects S3E evaluation board, but since there's a manual reset button you can get it to work)
* S3E P&R is having difficulties due to both DCM used, but it does meet timing. However I'll address that on next release, to speed up the implementation process.