Making a C64/C65 compatible computer

So, we have had HDMI-compatible video output working for some time. We even have the audio working on many monitors, but not all. There is something fishy with the audio output of the ADV7511 driver, when using certain TVs, monitors and HDMI capture devices. The symptom is either no audio, or no

Weiterlesen

Those who have been following along the MEGA65 story for a while will know that the MEGA65 has 384KB of main "fast chip" memory which is clocked at 40MHz, and is accessible by the VIC-IV, and that we also planned from the outset to have additional RAM.

The original Nexys4 boards had a kind of RAM

Weiterlesen

This short post is really one for the folks out there pulling their hair out with FPGA development in general, rather than the MEGA65 specifically.

I have had errors like the following a few times, and it always takes me a while to remember what the cause is:

ERROR: [Synth 8-2396] near character

Weiterlesen

I'm continuing to work on creating a tool to write updated bitstreams (or "cores", or whatever you like to call the things that turn an FPGA into an interesting computer Here's what it looks like after I got it working:

But let's go back to the beginning...

In a recent post, I confirmed that

Weiterlesen

The Real-Time Clock (RTC) chip that Trenz chose for the MEGA65 main board is different to the one we have on the MEGAphone. While the one on the MEGAphone proved easy to set, the one in the MEGA65 is resisting my efforts to be able to set the time.

The datasheet explains that you have to set the

Weiterlesen

The internal SD card slot has been working for ages, but we never managed to get the external one working when we had the sprint to bring the MEGA65 R2 board up last year. So I am trying to finally fix this.

It's been an interesting problem, with a few unexpected things.

First, I had to

Weiterlesen

As many reading will know, the German arm of the project has been running a fund raiser since mid-October last year, with the goal of funding the manufacture of the injection-moulding tooling to build the cases for the MEGA65.

The main concerns that people raised about this, was that it was rather

Weiterlesen

I am getting closer to being able to communicate with the QSPI flash, so that we can have the MEGA65 update its own bitstreams in the field. To recap the current situation:

1. Most of the signals to the flash are easy to connect to with the QSPI flash, except the clock, which is normally driven

Weiterlesen

So, in the last post, I implemented the ability to tell the MEGA65 to switch to a different bitstream. The next challenge is to make it possible for the MEGA65 to be able to re-program the contents of the flash memory, so that we can supply people with an updated bitstream, and make it super-easy

Weiterlesen

The MEGA65 is based on an FPGA. FPGAs are like a blank canvas that you load a hardware design into, with that design being typically stored in flash memory. Generally you don't notice this, because the whole process of loading the design into the FPGA and starting it, takes only about 0.3

Weiterlesen