![]() If you want to run the program your self with your own interfaces and joystick, I would love more data. Hopefully this will fix the bug in MAME that affects C-III Pages and not cause any regressions. Here is what MAME is doing as of today: SpeedĪfter going over the data here is what I am going to change MAME to do: Speed See the image below and notice how much noise is in the bitmaps: The Kola touch pad had the weirdest response to both versions of the sampling routine. When I filled in as much as the four rectangles as I could, I returned to the text screen and took a screen shot. The testing procedure was to start the program and wiggle the joystick while looking at the graphic screen (the G command). A black beauty, a delux joystick, a C&H joystick, and a Koala Touchpad. I have in my possession four “joysticks” to test. It does not do any scaling of the returned values to fit within the screen width or height. This program uses a slightly modified version of the sampling code found in most software. So I did what I always do, I wrote a test program to run on real hardware. Reading the code in MAME doesn’t really tell the whole story, and none of the values that are chosen are explained. This means it is now time to really try to understand the device. The author of C-III Pages (an early desktop publishing application for the Color Computer) discovered the mouse cursor would only go 7/8th across the width of the screen. I was recently told about a bug in MAME’s implementation of the Tandy Hi-Res Joystick interface. Posted in Uncategorized CoCo Max III Hi Res interface With a 5 cycle loop counter, this comes to a delay of about 111 microseconds. I now have two results from different Floppy Disk Controllers: 20 and 19. The records the counter and status to make available to a BASIC program for further processing. This will stop the loop and run my NMI handler. On the Color Computer this is tied to the Non-Maskable Interrupt line. When the write fails, the Floppy Disk Controller will produce an Interrupt Request signal. The loop will not actually count forever. Orcc #$50 turn off interrupts, keep motor spinning That is what I did, initiate write and then count forever: But if you know the disk write will error becuase of a write protect notch, all you really have to do is count. Normally after you issue the command to write to a sector, you prepare to start writing and then wait until the disk is ready. I wrote a Color Computer program that writes to a write protected disk on purpose. I wish I had an oscilloscope to measure things like this, but I don’t. The solution also was simple: properly emulate the delay between issuing a write command, and the INTRQ that happens when the write protect notch is covered.īut how long of a delay should it be? The floppy disk controller chip data sheet does not specify what is normal. OS-9 wont boot on a copy protected disk image. Posted in Uncategorized The Write Protect ProblemĪn interesting bug appeared on MAME Testers recently. MAME 0.246 is the first version to contain the fixes for the above. Special thanks to Pedro Pena for a screen capture. The comma need to be moved to the right one pixel. The lowercase letter j is the wrong shape. The lowercase letter i is the wrong shape. Over all the characters need to be moved one pixel up. The comma also needs to be moved one pixel to the right. Over all, the characters need to be moved a pixel up. The lowercase letter y is the wrong shape. The lowercase letter w is the wrong shape. ![]() The lowercase letter t is the wrong shape. The lowercase letter q is the wrong shape. The lowercase letter p is the wrong shape. The lowercase letter m has an extra pixel. The lowercase letter g is the wrong shape. It only needs to be moved one pixel to the right. Over all the characters need to be moved one pixel up and to the right. The three is missing a pixel on it’s stem. Over all the characters need to be pushed one pixel to the right and one pixel up to properly fit in their boxes. The stem of the number ’3′ is too short in MAME. First, here is the comparison between a real and MAME emulated CoCo 2. Using this device I can capture pixel perfect pictures of my CoCos and compare them to what MAME currently produces. One nice feature it has is to write the frame buffer to a PNG file. This device is a very configurable retro computer video to HDMI device. I was recently informed of some inaccuracies with the various VDG text screens emulated in MAME.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |