Alex's presentation from OzKFest 2015 covers the output of serial video data from Apple IIe and IIc computers and presents hardware and software to convert that data into a USB stream that can be displayed within a window on a laptop or other device.
Find out more on Alex's blog:
http://lukazi.blogspot.com.au/search?q=A2VideoStreamer
2. What is it?
• Hardware that sends Apple IIc or
IIe video serial stream over high
speed USB.
• Software that runs on desktops /
laptops / tablets and shows the
video feed.
3. The aim was to get a mobile
display for my IIc.
• DVD Player.
• Composite USB streamers.
• Original flat panels.
• LCD panels.
• iPad? What no video in? Arrhhh!!!
4. •Bulky.
•Not great use of screen space.
•Poor quality.
•Flickering.
•Noise / interference.
•Difficult to customise view size.
5. •Expensive.
•Hard to find.
•Poor contrast and no back light.
http://www.callapple.org/documentation/technical-notes/apple-c-flat-panel-lcd-conversion/
This will be going on my next Christmas wish list.
6. •Shows how hard it is to get something
that shows a reasonable picture.
http://quinndunki.com/blondihacks/?p=1998
http://www.eljavo.com/en/la-apple-c-a-color/
•LG Philips LB084S02 panel.
•Interesting option.
7. What problem do all of these options have in common?
COMPOSITE
Why?
•Not well suited to modern technology.
•Only monochrome on PAL IIc.
•I can go on and on and on …
Why deal with it when you don’t have to?
8. iPad WiFi or iPad USB?
•Suspect the lag on WiFi would be
too great.
•Streaming via USB is possible.
http://www.redmondpie.com/how-to-monitor-canon-eos-
dslr-camera-from-ipad-video/
http://www.exolabs.com/products.html
10. Analysing signals from the IIc video
port.
Checking to see which signals are
going to be ok to send digitally.
Expected to see a square 14M signal
but found a saw wave instead.
11. Logic Analyser Testing
Clock pulse does not look even but that is because this Logic
Analyser does not have a 14MHz (or multiple of) clock selection.
Will need to use the Apple II clock when streaming data.
12. Which graphics tool do I use to display the Apple II window?
Needs to be portable.
Knock something up and display a test pattern.
13. Microcontroller with high speed USB
Cypress EZ-USB FX2LP microcontroller
(CY7C68013A).
14MHz streaming over high speed USB
$10 device
Easy to connect
Lossless signal
No overhead with video protocols
Bypass NTSC / PAL processing
Modes:
‘Ports’ mode
‘Slave FIFO’ mode
GPIF - General Programmable Interface
'Slave FIFO' mode:
Synchronous
AUTOIN
USB side:
EndPoints
BULK, INTERRUPT or ISOCHRONOUS transfers
Buffers
Packet per transfer
Queues
Programming:
RAM
EEPROM
USB from application
14. Sampling
14MHz -> Clock
WNDW Bit[0] -> Line and page sync
SEROUT Bit[1] -> Data bit
CREF Bit[2] -> Colour reference signal. Needed?
GR Bit[3] -> Graphics mode
Spare Bit[4] -> Maybe for colour - TEXT?
Spare Bit[5] -> Maybe for colour - SEBG?
Spare Bit[6] -> Maybe for colour - LDPS?
Spare Bit[7] -> Spare
Note: For monochrome only the clock and bits 0 and 1 are needed.
15. Development and Testing
Firmware Software
Keil uVision2 Microsoft Visual C++ 2008
Cypress USB examples are great if you have the professional versions of uVision2
and Visual Studio but if you have the free versions then they are a pain in the butt.
That’s the difference you get when using products from a company that targets the
commercial sector as opposed to the education sector.
16. if (EndPt->FinishDataXfer(buffers[i], rLen, &inOvLap[i], contexts[i])) {
BytesXferred += len;
for (int iByte = 0; iByte < rLen; iByte++) {
if (!bProcessData) {
if (!(buffers[i][iByte] & 1)) {
if (iDisplayBlank > 8000) {
iDisplayY = 191;
}
else {
if (iDisplayY > 0)
iDisplayY -= 1;
}
// iDisplayX = -7; // 80 column setting.
iDisplayX = -13; // 40 column setting.
iDisplayBlank = 0;
bProcessData = TRUE;
}
else {
iDisplayBlank += 1;
}
}
if (bProcessData) {
if (iDisplayX < 560) {
if (iDisplayX >= 0) {
if (!(buffers[i][iByte] & 2)) {
color[iDisplayY][iDisplayX][0] = 255;
color[iDisplayY][iDisplayX][1] = 255;
color[iDisplayY][iDisplayX][2] = 255;
}
else {
color[iDisplayY][iDisplayX][0] = 0;
color[iDisplayY][iDisplayX][1] = 0;
color[iDisplayY][iDisplayX][2] = 0;
}
}
iDisplayX += 1;
}
else {
bProcessData = FALSE;
}
}
}
}
Take out the Window, OpenGL and USB code and the remaining code is
quite short. The data processing part is very simple.
18. ResultsText
Monochrome
text can be any
colour
including
white, green or
amber.
Colour
display is
still a
work in
progress.
Colour
Will try and match something like AppleWin output.
Normal 50% Scan Lines
19. Issues
• Still working on getting a colour solution.
• Could only get BULK USB working. Prefer to get ISOCHRONOUS transfers
working.
• 80 Columns starts a character earlier than 40 Columns even though they
both have the same line width.
• Need to crapify (technical word) the picture to make it look more like a
vintage monitor. This is the same issue that emulator developers have.
20. Extra Information
WNDW signal is good for synchronisation because it changes state just before
the data begins but it can not be used to determine the end of line because
it finishes before the data ends.
LDPS signal can be used to determine if 80 Columns/HGR or 40 Columns/GR
is being used. Pulse is half the size for 80 Columns / HGR.
To determine which graphics mode is selected these signal lines are needed.
Will this be needed for colour processing?
Mode TEXT Mixed GR/TEXT Mixed HGR/TEXTHGR DHGR
GR = 0 5/0 5/0 5 5
TEXT = 5 0/5 0/5 0 5*
SEBG = pulse 5/5 0/0 0 0
* TEXT signal is high in DHGR mode.
21. Design Note
Using SEROUT and accompanying signals is not difficult. I encourage you to
give it a go. I’ve used this method to build a better streamer but I would like to
see what others can do.
VGA cards like the Guimauve 2000 and Nishida Radio’s VGA options already
process serial data. They use FPGAs to do the processing but what about
using other devices such as a Raspberry Pi or a PSoC or a dedicated VGA
chip?
As screen technology has progressed video adaptors have been built
to take up the slack from dwindling numbers of the original display
solutions. As screen sizes increase the less appealing they for me as
vintage monitor replacements. What sparks my interest is the current
tablet market because the screens are of a similar size to our old
favourites and the high resolutions can be used to reduce pixellation.
22. I thought that video streaming to the iPad would take one to two days to set up.
It has taken quite a bit longer and I’m only half way there.
To be continued …
http://lukazi.blogspot.com.au/search?q=A2VideoStreamer
Conclusion
