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Macintosh Quadra 840AV and Macintosh Centris 660AV

July 29, 1993

Prepared by Noah Price, Hardware Design Team (noah@apple.com)

Contributions from Fernando Urbina, Software Team (nano@apple.com)

Comparison of AV models

 

Macintosh Centris 660AV

Macintosh Quadra 840AV

Enclosure

Same as Centris 610

Same as Quadra 800

Processors

CPU

Motorola MC68040RC

Motorola MC68040RC

CPU Speed

25 MHz

40 MHz

Hardware Floating Point

Included

Included

DSP

AT&T DSP3210

AT&T DSP3210

DSP Speed

55.5 MHz

66.6667 MHz

Main Memory

Onboard DRAM

4 MBytes

none

Expansion DRAM SIMMs

Two 72-pin SIMMs(1)

Four 72-pin SIMMs(1)

Maximum DRAM capacity

68 MBytes

128 MBytes

Expansion DRAM Speed

70 ns

60 ns

Video & Graphics

Onboard VRAM

1 MB

1 MB

Expansion VRAM SIMMs

none

1 MB (Four 256K SIMMs)

Expansion VRAM Speed

n/a

80 ns

Expansion

NuBus

1 slot(2)

3 slots

DAV(3)

1 slot(2)

1 connector

Power

Power Supply

85 W

200 W

Trickle Power

none

Yes(4)

Power Control

Hard power

Soft power(5)

Monitor Outlet

Unswitched

Switched

NOTES:

  1. Both models use 32-bit wide 72-pin SIMMs. For electrical loading and timing reasons, composite SIMMs are not supported.
  2. The NuBus slot and DAV connector are optional on the Centris 660AV. A NuBus adapter card, similar to the adapter for the Centris 610, must be added. This card provides a single NuBus slot in line with a DAV connector. Like the Centris 610, the Centris 660AV is designed to accomodate a 7" NuBus card.
  3. DAV - Digital Audio Video connector. The DAV connector is in line with a NuBus slot, and provides digital video in YUV format and digital audio.
  4. Trickle Power is a +5V supply that is present whenever the computer is plugged in. When available, it is automatically used instead of the battery to maintain parameter RAM. Trickle power is also provided to NuBus, per NuBus 90, and to GeoPort for use in an external telephone interface.
  5. Soft power control has been enhanced. The Quadra 840AV may be turned on or off from either the keyboard power switch (which puts up a confirmation dialog before shutting down) or the front panel switch. Software control of on/off features is now available in the "Auto Power On/Off" control panel. This includes automatically turning the computer on or off at a specified time, and automatically powering back on after a power failure.

I/O Features Overview

Both AV models support Direct Memory Access (DMA). Serial (including LocalTalk and GeoPort), 53C94 SCSI, Ethernet, floppy, and audio are all supported with DMA drivers.

 

The version 4.3 SCSI Manager supports fully asynchronous SCSI transactions with extensions to the Applications Programmer Interface (API). A new SCSI driver is required on the hard drive for full performance benefits. This driver may be installed on existing Apple SCSI hard drives using the new HD SC Setup.

Audio Features Overview

Both AV models support 16-bit Stereo audio input and output. Hardware sample rates include 48 KHz and CD standard 44.1 KHz.

Output port

Mini-stereo jack, line level

Input port

Mini-stereo jack (plus power), line level

Internal

CD Audio 4-pin stereo header

Video Features Overview

Video Output

RGB (DB-15 connector)
Composite (RCA connector)
S-Video (4-pin mini-DIN connector)

Video Output Formats

RGB, NTSC or PAL
("SECAM" TVs can be supported with an adapter on the RGB output using PAL timing.)

NTSC/PAL "Flicker Free" (Convolution)

Yes (up to 8 bpp, without video-in)

Video Input

Composite (RCA connector)
S-Video (7-pin mini-DIN with power and IIC control, compatible with 4-pin mini-DIN)

Video Input Formats

NTSC, PAL or SECAM

Largest Monitor

21" (1152 x 870)

Maximum Graphics Bit Depth

32 bits/pixel (see details per model below)

Video Play-through Bit Depths

8 bits/pixel greyscale or 16 bits/pixel color

Video Output Display Support

The AV models support a wide range of monitors. The built-in monitor support is detailed in the table below. For the AV models, video-in refers live video from one of the input jacks, video out refers to live video playthrough, and graphics refers to traditional Macintosh generated video output (windows, desktop, etc.).

To accomodate displaying live video in a window with graphics, both models have a split frame buffer architecture. Video-in uses one-half of the video memory and graphics uses the other half. To achieve the highest graphics bit depth, the two halves are often used together for graphics. Consequently, for many monitors video-in is not available when displaying graphics at the highest bit depth. When displaying live video, the two frame buffers are merged so the video-input appears as a window on the graphics display.

Note that the bit depth for graphics may be different than the bit depth for video. For example, on the 13" or 14" RGB display, you can display up to 8-bit graphics when video-in is enabled. However, you can view a 16-bit video input window on this display at the same time.

The machines can drive an NTSC or PAL monitor directly, without the use of an encoder box. In order for that feature to be enabled, the display resolution should be either 512x384 or 640x480 for NTSC, or 640x480 or 768x576 for PAL. Hence the different resolutions available for each display.

 

Notes:

1) The Macintosh Centris 660AV always has 1 MByte of VRAM.

2) The Macintosh Quadra 840AV comes standard with 1 MByte of VRAM and may be expanded to 2 MBytes of VRAM. Four 80 ns 256K VRAM SIMMs are required.

3) Where multiple resolutions are available, an asterisk (*) indicates the standard resolution. Additional resolutions allow you to display more colors by only using a portion of the monitor. Select the resolution by using the Options dialog of the Monitors Control Panel. You must reboot to change resolutions. The size of the pixels will not change in these alternate modes. Instead, a black border will appear around the smaller active video area.

4) A "Flicker-free" mode (sometimes referred to as Apple Convolution) is available when displaying on a TV. This mode is available at up to 8 bits/pixel and is not available when using video-in.

5) bpp is Bits Per Pixel. A range is given in table below, indicating which of the following are available:

     1 bpp - Black & White

      2 bpp - 4 colors or greys

      4 bpp - 16 colors or greys

      8 bpp - 256 colors or greys (greys only for Video in)

      16 bpp - Thousands of colors (5 bits each of R, G, and B)

      32 bpp - Millions of colors (8 bits each of R, G, and B)

 

6) Both the video and graphics portions of VRAM are often used together to display graphics at the highest available bit depth. In the table below, the range of graphics bit depths is marked with # when video-in is available at the maximum graphics bit depth. In all other cases video-in is not available when using the highest graphics bit depth.

1 MB VRAM

2 MB VRAM

Graphics

Video in

Graphics

Video in

Display

Resolution

(bpp)

(bpp)

(bpp)

(bpp)

12" RGB

512x384*

1-32

8-16

1-32

8-16

560x384

1-32

8-16

1-32

8-16

13" or 14" RGB & 12" Monochrome

512x384

1-32

8-16

1-32

8-16

640x400

1-32

8-16

1-32

8-16

640x480*

1-16

8-16

1-32

8-16

15" Portrait, Full-Page Monochrome

512x384

1-8#

8-16

1-8#

8-16

640x480

1-8#

8-16

1-8#

8-16

640x870*

1-8

8-16

1-8#

8-16

15" Portrai, Full-Page RGB

640x870*

1-8

8-16

1-16

8-16

16" RGB

512x384

1-32

8-16

1-32

8-16

640x480

1-16

8-16

1-32

8-16

768x576

1-16

8-16

1-32

8-16

832x624

1-16

8-16

1-32

8-16

19" RGB

1024x768*

1-8

8

1-16

8

21" Two-Page, Monochrome

512x384

1-8#

8

1-8#

8

640x480

1-8#

8

1-8#

8

768x576

1-4#

8

1-4#

8

1152x870

1-8

8

1-8#

8

21" Two-Page, RGB

512x384

1-16

8

1-16

8

640x480

1-16

8

1-16

8

768x576

1-4#

8

1-4#

8

1152x870

1-8

8

1-16

8

VGA/SVGA Displays

640x480*

1-16

8-16

1-32

8-16

56Hz

800x600

1-16

8-16

1-32

8-16

72Hz

800x600

1-16

8-16

1-32

8-16

60Hz

1024x768

1-8

8

1-16

8

70Hz

1024x768

1-8

8

1-16

8

Composite and S-Video Output Modes

NTSC convolved (flicker-free mode)

Underscan (Safetitle)

512x384

1-8

NA

1-8

NA

Overscan (Fullframe)

640x480*

1-8

NA

1-8

NA

NTSC non-convolved

Underscan (Safetitle)

512x384

1-32

8-16

1-32

8-16

Overscan (Fullframe)

640x480*

1-16

8-16

1-32

8-16

PAL convolved (flicker-free mode)

Underscan (Safetitle)

640x480

1-8

NA

1-8

NA

Overscan (Fullframe)

768x576*

1-8

NA

1-8

NA

PAL non-convolved

Underscan (Safetitle)

640x480

1-16

8-16

1-32

8-16

Overscan (Fullframe)

768x576*

1-16

8-16

1-32

8-16

* Default resolution. See note 3 above.

# Video-in is availble at the highest graphics bit depth.

See note 6 above.

Comments

Please refer comments to Noah Price at noah@apple.com. Please understand that I may not be able to respond to everyone individually. However, comments or questions may be incorporated in future revisions.


Last update 03-Feb-1999
noah-web@theprices.net