RGB to hdmi video adapter
The Aquarius RGB to HDMI Adapter Board will be an after-market upgrade to the stock Aquarius that replaces the original RF modulator with a high quality, high resolution output solution. For now, there is no AUDIO output via HDMI, so a separate HDMI Audio Inserter must be used OR a standalone pair of desktop speakers.
After I completed the Aquarius Composite Video Adapter, I decided the next step was to try to improve the output from the Aquarius to display on monitors that separated the RGB signals for higher quality signal. I began reviewing older posts from Bruce Abbott on the AtariAge.com forums, and found that he had developed a working model in 2014. It had a few problems, namely that characters with full-height pixels in them would render with a faint vertical bar on their left side. He resolved this issue later in about 2017 by adding a 74LS165 shift register on the INPUT side... dubbed the V4+ it included both RGB and composite out through a custom DIN connector. That effort was progressing SLOWLY and unfruitfully. I even went so far as to have a set of prototype PCBs made, to no avail.
One day a video for the Amiga RGBtoHDMI adapter came across my YouTube feed. I traced the sources back to Hoglet67's RGBtoHDMI project, which uses a RaspberryPi Zero with a custom Pi Hat with a CPLD that samples video pulses from legacy RGB video sources and renders them into the Pi's graphics buffer and out through the mini-HDMI port. I had a set of their boards printed, sourced the parts, made the SMD solder mask, and built one. And it worked!
Status (19 APR 2021)
First prototype (v1.0a) successfully installed in a client's machine. Updates/tweaks will be made in v1.0b, but existing boards will be used until they are gone.
Issues (19 APR 2021)
C1 10uF SMT capacitor shorts out on RPi's mini HDMI port
v1.0a Fix: insulate with Kapton tape
v1.0b Fix: rework position of cap right, above fourth top pin on CPLD
CPLD index mark is not visible due to via drill
v1.0a Fix: know that the CPLD index is in the upper left of the SMT profile
v1.0b Fix: move via or add more prominent silkscreen dot inside CPLD area
Soldermask covers copper jumpers that enable CPLD programming; looks like they AREN'T connected when they are
v1.0a Fix: ignore or carefully scrape off solder mask AND/OR add solder blob across pads
v1.0b Fix: remove solder mask over those traces
Missing R7 rom core design; brings GPIO0 low with a 1k resistor
v1.0a Fix: bodge a 1/4w 1K resistor between pins 7 & 8 on the inside, non-reset row, bottom of the board
v1.0b Fix: add R6, a 0408 1k SMT resistor above pins 7 & 8 on the inside, non-reset row, TOP of board
The TEA1002 has to be removed and soldered to a small riser PCB which gives a pin header for the necessary RGB signals. At some point, the TEA1002 MIGHT not be needed at all, but testing will have to be done for that.
Audio out comes from a 3.5mm / 1/8" audio jack on the daughtercard. A slimline stereo audio cable is trailed out the TV out port on the Aquarius, and can be attached to speakers or to an HDMI Audio Inserter device.
A mini-HDMI cable is included and plugs into an exposed mini-HDMI jack in the TV out port on the Aquarius.
Not all HDMI TVs/Monitors behave the same. Some tweaking of the settings sometimes has to occur before closing up the Aquarius.
Let's not get ahead of ourselves...