Macintosh II High-Resolution Video Card: New Features

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TOPIC -----------------------------------------

This article describes the new features of the Macintosh II High-Resolution
video card.

DISCUSSION ------------------------------------

The Macintosh II High-Resolution Display Video Card is the cost-reduced
replacement for the previous 4- and 8-bit Macintosh II Video Card (M0211 and
M5640). This new card is sold in 4- and 8-bit configurations (M0322 and M0324,

This new release is fully compatible with the previous card when used with
Apple's video drivers, monitors, and cable. Applications that make direct
hardware calls may not work with the revised card. Also, third-party video
cables may need to be changed (see item 2 below).

New Features

The following minor features were added to the card. They should not have a
major impact on the typical use of these cards.

1. Monitor Type Detection

At startup, the High-Resolution Display Video Card senses the monitor type by
sensing a previously unused signal line: pin 4 in the D-15 video connector. The
selection is as follows:

SENSE 0 Monitor Type
(Pin 4)
1 or N/C NTSC Timing RGB video out
0 12- and 13-inch Monitor Timing

(Note: Some third-party cables may not be wired correctly to support this
detection scheme.)

2. New Driver Level Control of RS-170 RGB Video

The card supports two RGB interlaced video resolutions:

- 512 by 384 pixel (default mode) and
- 640 by 480 pixels

To select the higher resolution, the system needs the new Monitor CDEV and Slot
Manager supplied with the 32-bit QuickDraw, plus the correct cable
configuration (see item 1). Selection is made by choosing the monitor icon
(highlighted borders) connected to the Macintosh II High-Resolution Video Card
and clicking on the Options button. A dialog box will appear with the options.

In addition, the card only produces RGB interlaced video in the 4- and 8-bit

3. Enhanced Firmware

In addition to the scanning modes mentioned above, the card supports
uncorrected gamma, has an integrated gamma directory, and implements a new set
of driver calls to support these new features.

Published Date: Feb 18, 2012