I'm porting this to MiSTer and wondering if anyone would want to port to ulx3s https://github.com/menloparkinnovation/menlo_gigatron
@lawrie @Speccery I got ti99/4a display video on st7789. Complete text mode is visible, a bit of color stripes from title screen are cropped. For eventual pull I don't know is the implementation following style, as st7789 support is pulled out of sys module to toplevel https://github.com/emard/icy99
Here it is running Microsoft Basic:
Z80 SBC By Grant Searle
Cold or warm start (C or W)? C
Memory top?
Z80 BASIC Ver 4.7b
Copyright (C) 1978 by Microsoft
32382 Bytes free
Ok
10 print "hello"
run
hello
Ok
It is an attempt to redo my Z80 retro computers with a common code base, starting with a template, and then adding the specifics for each computer or game console.
I am using @pnru_gitlab's 6850 ACIA implementation as the uart, as that is compatible with computers such as the RC2014
So I can run the roms from that project - https://github.com/RC2014Z80/RC2014/tree/master/ROMs/Factory
@emard would know that he tried
I think currently fastest way is using ESP32 to program it
@splinedrive external JTAG pins are there to connect external JTAG programmer. it can be much faster if fast software is used. I tried FT2232 with diamond, it works as native programmer but diamond programs FPGA slowly compared to other programmers using same FT2232 hardware... Goran uses ext JTAG during prototype troubleshooting when only FPGA is soldered onboard without any other parts onboard. Ext JTAG can be used if USB-FTDI and WIFI methods are not working or supported. I wanted that user never runs out of options to program ULX3S :)
I have written a commentary on the top-level module for my Z80 template - https://github.com/lawrie/ulx3s_z80_template/blob/main/top.md
The idea now is to recreate my Z80 retro computers using this template and to add some new ones.
I will probably start with recreating the TRS-80 Model 1 as that is about the simplest of the Z80 retro computers.
There are some problems with the keyboard
@emard With the old version I got ecppll to generate a 25MHz clock for the VGA (plus 125MHz for HDMI) and a 28MHz clock, which I then divide to produce the CPU clock. Your ecp5pll gives an error when I try to generate the 28MHz clock, so I am currently using the 25MHz clock divided by 8 for the CPU. I don't know if that is causing the keyboard problem.
With 2-stage PLL, you need to create some 28-multplider-divider frequency first and then in second stage take that as input and get 28 exactly. For this you need some try and error, experiment with 2nd stage first to find out which input frequency will provide 28 as output. besides 28 maybe 282, 283/2 and similar inputs will. For example to create 32.0 MHz at 2nd stage I need 40MHz input which can be exactly generated by 1st stage from 25MHz input
Hi, Do you know a pmod for hdmi/dvi (no vga to hdmi)? I found only an article https://hackaday.io/page/5702-dvi-hdmi-pmod-for-an-ice40-fpga. I want to arm my ice40s with hdmi or arm my ecpix-5 with it. The ecpix has a hdmi controller on board :(. Maybe a pmod with and without levelshifters. Or it would be also cool to have more hdmi ports on our ulx3s.
There is this - https://1bitsquared.com/products/pmod-digital-video-interface, which I have used on the icebreaker.