Second Revision MEGA65 Mainboards

Things are getting exciting again! We have the first two samples of the second revision of the MEGA65 main board.  This incorporates fixes to all the known problems of the first board, as well as a bunch of pleasant extras.  

But first, we are super appreciative for everything that Antti and the rest of the crew at Trenz Electronics have done to get us this far.  Without their dedication and kind support, we would not have a MEGA65 mainboard at all, let alone one that is so nice for all that we want to do.

Now, onto the first pictures:

So, there are quite a few changes from the first revision:

1. Power cord now comes in from the back, instead of from the side, which makes things just nicer and neater.

2. Cartridge port cut-out is now wider, to allow even the fattest cartridges to be more easily connected.

3. VGA and HDMI connectors now have enough space to be both connected without causing trouble.  It will in principle be possible to drive the two independently with different pictures, when we get that far.  This is more of concern to those who want to be able to run a C128 core with simultaneous 40 and 80 column displays.

4. Missing pull-ups on the joystick ports, cartridge port and floppy connectors have all been added.

5. SD card slot and microSD card slot both added, which is very welcome as in the rush to get the first revision ready, the SD card was left as an "after factory add-on", i.e., had to be hacked on.  The MEGA65 will be able to use both SD cards at the same time, with dual-card support already in the VHDL, and will come in due course to the Hypervisor. For now, it just tries the second slot if there is nothing found in the first slot.  The internal one is a full-size SD card, so strange SD cards, like those ones with Wi-Fi onboard should be possible to use.

6. PMOD GPIO connectors that allow internal expansions.  We expect, for example, to be able to make an adapter that will allow the installation of a cellular modem, 8266 Wifi or RN52 bluetooth adapter, based on the work on the phone/handheld version, thus allowing wireless networking for the desktop MEGA65.  This is just one of the many little synergies that come from working on both versions at the same time.

7. Dual power connectors for internal floppy drives.  Again, we forgot in the rush last time to include any of these.

8. On-board real-time-clock (thus the battery holder) so that you can easily remember just how many years of happy use you have extracted from your MEGA65.

9. The C64 and C65 compatible keyboard connectors have been replaced by the 8-bit 8-pin serial interface to the MEGA65's custom mechanical keyboard. It will be possible to make an adaptor to still use a C64 or C65 original keyboard that connects to this interface.

10. Reset button tells the CPU not the FPGA to restart, i.e., without losing the contents of RAM.  In short, it will work as a proper reset button.

11. Addition of a 2nd "Little Brother" FPGA that can be used to recover from bricked FPGA configuration, without having to even open the case.  This will also make it much easier to flash updates onto the MEGA65 for end-users.

12. Addition of support for an internal speaker on J19, for when you don't have a monitor with speakers.

13. Addition of an extra I2C bus for other expansion peripherals on J18.

14. Fits our wonderful new cases just fine.

15. Lots of other little and not so little fixes.

Now the biggest problem is I don't get to Germany until Saturday, so have to wait impatiently in the meantime before I get to play with them :)

What I have done, though, is create a mega65r2 target in the VHDL source, which Antti has already confirmed gets a working video display on the VGA output.