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1990-01-26
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(c) Copyright 1989 Commodore-Amiga, Inc. All rights reserved.
The information contained herein is subject to change without notice, and
is provided "as is" without warranty of any kind, either expressed or implied.
The entire risk as to the use of this information is assumed by the user.
PAL and NTSC Differences
by Carolyn Scheppner
HARDWARE
The parts list below has been updated to include NTSC and PAL components for
the 2-layer A2000. Members of the Developer Support Program located in the
U.S. may order PAL parts from CATS (for more information, call the CATS
number listed on your Hardware Price list). Overseas developers should check
with their local Commodore office for NTSC parts availability.
4-Layer 2-Layer
A1000 A2000 A500 A2000
AGNUS NTSC part# 252125-01 252125-01 318070-01 318070-01
PAL part# 252362-01 252362-01 318071-01 318071-01
CRYSTAL NTSC part# 325566-14 325566-12 325566-14 325566-12
PAL part# 252344-01 252344-01 252344-01 252344-01
POWER 110V USA 327173-01 internal 312503-01 internal
240V BSI -02 jumper -02 jumper
220V VDE -03 on power -03 on power
220V SEV -04 supply -04 supply
Note: the Enhanced Chip Set, which includes a 1 MG Agnus chip, will allow
external switching between PAL and NTSC video modes on the 2-layer A2000.
SOFTWARE
There are some software differences that you should keep in mind while
developing products for the international market:
- Many international keyboards have different RAWKEY codes from
the US keyboard. Use CON: or console.device for automatic
translation to the correct ASCII values.
- Define your char variables and arrays as UBYTE. This will prevent
sign extension on 8-bit ascii international characters. Test all
of your text input routines with international characters.
You can type international characters. You can type international
characters on a US keyboard by using the deadkeys (for example, ALT/K
then O will make an O with an umlaut accent).
- PAL screens have more lines (256, 512 interlace). Use the 1.2
Intuition GetScreenData function to get a copy of the Workbench Screen
structure, or check Gfx->NormalDisplayRows which contains the height
used for a non-interlaced Workbench screen. Be careful when doing
any low level graphics programming based on the beam counter.
Remember the counter will go higher on a PAL machine.
- When using a clock constant in audio period-to-frequency
calculations, remember that a different clock constant must be
used on PAL machines. Check GfxBase->DisplayFlags to see if
you are running on a PAL machine. The NTSC clock constant is
3.579545 MHz. The PAL constant is 3.546895 MHz.