This project is a VGA card for Apple II/II+ and //e computers to output a crisp RGB signal to a VGA monitor instead of having to rely on the composite output. This is accomplished by snooping the 6502 bus and creating a shadow copy of the video memory within a Raspberry Pi Pico, then processing the raw video memory contents to output a "perfect" signal.
These features are currently supported:
Generates a 640x480@60 VGA signal with 3 bits per color channel using resistor DACs
Text mode (monochrome)
Lo-res mode with no color fringing between the chunky pixels
Hi-res mode with simulated NTSC artifact color
Mixed lo-res and hi-res modes with monochrome text and no color fringing
Double hi-res and 80 column mode on the //e only
# Bill Of Materiels
https://www.amazon.com/dp/B07W3ZTPZ6?psc=1&ref=ppx_yo2ov_dt_b_product_details
Resistors are not polarized so they can be installed either direction. I like to start with the 100ohm resistors and work my way up to the 10K ohm resistors. The gold band is the percentage of accuracy. To read a resistor, start at the opposite side of the gold band.
47 ohm resistors -- qty 2 - Colors Yellow Violet Black
510 ohm resistors - qty 3 - Colors Green Brown Brown
1K ohm resistors -- qty 6 - Colors Brown Black Red
2K ohm resistors -- qty 3 - Colors Red Black Red
10K ohm resistors - qty 4 - Colors Brown Black Orange
Bend the metal wires at a 90 degree angle on each side of the resistor body.
Place the resistor into the resistor location until it is flush with the PCB.
Turn the board over holding the resistor in its place and bend the wires outward just slightly so the resistor can not back out of the holes.
While the bottom of the board is facing up flat on your workspace, solder each of the two wires on the resistor.
Make sure your solder stays only on the resistor wire and the hole.
Cut the excess lead off the resistor. Repeat this procedure for all of the resistors.
Insert the Voltage Regulator and fold it over so it lays flat on its back.
Place the small screw into the top hole and through the board.
Place the nut on the screw on the back of the board and tighten down.
Solder all 3 pins and cut the extra leads short with the board.
The socket has a notch on one end that matches the PCB.
Place one socket into position and while holding the socket, turn the board over and lay flat on the table.
Hold the board level and solder 1 pin down. Turn the board over and check that the board is flush with the PCB.
If not, apply heat to the pin while pushing the socket flush to the PCB
Solder the remaining pins on the socket and repeat for the other 2 sockets
Install the three .1uF caps into their locations. The caps are labeled 104 and are not polarized so they can be installed either way.
Fit as flush as possible, bend the 2 wires apart a little so the capacitor does not fall out, turn the board over and set it on your workspace.
Solder the leads onto the PCB and cut away the excess lead length.
It is cylinder shaped and both leads protrude from the same side and are labeled 10uF.
There are two ways to tell the + and - leads.
First, looking at the leads, the + is longer than the – lead.
Secondly, there is a large white arrow pointing to the - lead.
Install flush with the PCB and fold it over so it lays between the .1uF cap and the voltage regulator.
Then bend the two leads slightly apart from one another.
Turn the board over and solder onto the PCB. Cut the excess lead on the capacitor.
Place the two 20 pin stand offs onto the board.
Then place the Pico onto the stand offs and make sure everything fits flush.
The Pico should be facing with the USB connector towards the VGA connector location.
Solder the 40 pins onto the Pico then hold down the Pico, flip the board and solder the pins to the PCB
The VGA connector has 3 rows of pins.
Insert flush with PCB, turn and solder the inside row first, followed by the outer 2 rows.
Check your work, and then solder the support tabs down.
You will need to pin the pins slightly inwards to align with the sockets.
Check for bent pins. Check for missing solder points
Solderfest 202/// all Pico chips are preprogrammed for the apple //e and will work on the apple ][ plus
If you wish to program or update:
1. Press and hold the BOOTSEL button on the Pico while plugging into PC
2. A drive will appear on the PC called RPI-RPI2. Simply drag the *.UF2 firmware file to the RPI drive.
3. The RPI drive will then disappear
4. Remove the USB cable place the Apple ][ VGA card in your Apple ][
Original design by Mark Aikens. Some minor modifications were made and a board layout made using original PI Pico source code. All parts are through hole for easy assembly. No surface mount components, simple to build.
https://github.com/markadev/AppleII-VGA