Image Map Image Map
Results 1 to 6 of 6

Thread: Difference between PAL and NTSC IIe

  1. #1
    Join Date
    Sep 2009
    Location
    Coventry, UK
    Posts
    119

    Default Difference between PAL and NTSC IIe

    Hi all,

    Couple of questions :

    Is there a timing difference between the US NTSC IIe and the UK PAL machines that would affect expansion cards plugged into the card bus? I recently re-engineered a simple SD card interface (to replace the original PLCC XC9572XL chip with a VQFP one). The produced boards will not work correctly on my UK PAL IIe machines, but have sent one to a friend who has an NTSC IIe, though with a UK PSU, and the card works absolutely fine.

    As a development I'm also trying to produce a version that has a microcontroller and uses FATFS to access the .po file on a FAT filesystem, that also seems to experience some of the same symptoms such as repetedly dropping to the monito prompt, oddly you can try booring the thing several times and it will drop to the prompt at exactly the same point after reading most of the first block. The code running on the microcontroller I'm pretty sure is working correctly as it's basically the same code I have been using for my DragonMMC board, which is deployed and in the wild, being used by end users So It's more the exchange of data with the Apple end of things that is bugging out.

    Couple of points both boards do have a 74LS245 on the data bus, with DIR tied to R/W and /E controlled by a CPLD pin, so that the 245 is only enabled for ranges that the card is dealing with. I've also implemented the flipflop for the $C800 memory, and that seems to be working correctly.

    Both boards are trying to use the same 32MB prodos 2.4.1 HDD image, which my friend uses on his NTSC machine, I have downloaded and transfered the 2.4.1 prodos floppy image with ADTPro and that boots from floppy without problems, so I know that both my IIe machines will boot prodos correctly.

    Is there any difference between the NTSC and PAL ROMS? Especially when converting one of the machines to an enhanced model (using a WD65C02, yes I have bent pin 1 out of the socket and pulled up pin 36), the machine seems to boot OK and will boot from floppy etc, just wanted to know if there are only one set of ROMS for this.

    Does anyone happen to have a copy of the (complete) schematic for the PAL / UK IIe? as the only ones I can find on the net are for the NTSC / US machine.

    Cheers.

    Phill.

  2. #2
    Join Date
    Jun 2017
    Location
    Karlsruhe, West-Germany
    Posts
    9

    Default

    Quote Originally Posted by prime View Post
    Is there a timing difference between the US NTSC IIe and the UK PAL machines that would affect expansion cards plugged into the card bus?
    I don't know british IIe, but my first IIe was an US Revision A and some others are german Revision B.

    There are some differences between NTSC and PAL mainboards: the first is the oscillator: 14.25045MHz on the European IIe (PAL) and 14.31818MHz on the US NTSC mainboard. There is another difference: the IOU is internally different: the US IOU generates 60Hz frame rate, the european IOU (PAL) generates 50Hz frame rate. You can change these IOUs. My own revison A motherboard killed the IOU back in the 1980s and I changed to a PAL version without any problem.

    Quote Originally Posted by prime View Post
    Is there any difference between the NTSC and PAL ROMS? Especially when converting one of the machines to an enhanced model (using a WD65C02, yes I have bent pin 1 out of the socket and pulled up pin 36), the machine seems to boot OK and will boot from floppy etc, just wanted to know if there are only one set of ROMS for this.
    The firmware ROMs are the same, AFAIK. Just the video and keyboard ROMs are different.

    Regards, Ralf
    Last edited by RalfK; November 2nd, 2017 at 01:50 PM.

  3. #3

    Default

    Quote Originally Posted by prime View Post
    Is there any difference between the NTSC and PAL ROMS?
    What's the part numbers on your ROMs? I see these in Asimov:
    emulators/rom_images/2716_APPLE-IIe-0341-0152-A_PAL_SWE_FIN.bin
    emulators/rom_images/2764_APPLE-IIe-0341-0162-A_PAL_SWE_FIN.bin
    Suggesting there was a PAL-specific set at least for Sweden/Finland use.

  4. #4

    Default

    I don't know if it's related but the IOU chip is definitely PAL or NTSC specific. This difference caused me problems. See
    http://www.classic-computers.org.nz/...creen-sway.htm

    Tez
    ------------------------------------------------
    My vintage collection: http://classic-computers.org.nz/collection/
    My vintage activities blog: http://www.classic-computers.org.nz/blog/
    Twitter: @classiccomputNZ ; YouTube Videos: (click here)


  5. #5

    Default

    One now wonders what difference there is between the '20, '21 and '22.
    Doing some surfing, I came on this page:
    http://comp.sys.apple2.narkive.com/x...e-iou-mmu-chip
    Also look at the manual:
    http://www.applelogic.org/files/AIIETECHREF3.pdf
    It clearly states this chip controls 'Video Blanking'. ( see page 166 and 167 )
    These are specifically 50Hz and 60Hz related. This would be done with a counter inside
    the chip.
    Clearly something to keep in mind for the future.
    Dwight

  6. #6
    Join Date
    Sep 2016
    Location
    Melbourne, Australia
    Posts
    306

    Default

    You find find a pdf for both the ntsc and euro version of the 2e here
    ftp://ftp.apple.asimov.net/pub/apple...re/schematics/

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •