Watch for falling links!
The video hardware for all three CPUs, the Centris 610 (C610), Centris 650 (C650) and Quadra 800 (Q800), is virtually identical. The only exception is that the C610 only requires 100 ns VRAM, while the C650 and Q800 require 80 ns VRAM.
The maximum supported pixel depth is 16 bpp. This is not a matter of the amount of VRAM in the machine - it is a hardware limitation The RAM/DAC used by all three machines simply does not include the hardware required to do 24 bpp on any display. The same is true for the lack of support for Apple convolution - the hardware necessary to do this is not present in the machine.
24 bpp support was dropped for a number of reasons:
Convolution support was dropped primarily for cost reasons, and also because it is very rarely used. NTSC and PAL timing support are still offered, however. The C610, C650, and Q800 do support all the monitor types supported by the Q950. This includes support for a 1024 x 768 resolution on 19-inch displays (which was not provided by the Q700).
One area that was positively impacted was performance. At the same processor clock speed, the video section of these new machines outperforms the video section of the older Quadras. (I.e., video performance on the C650 is better than the Q700, and on the Q800 is better than the Q950.) Due to an improved video memory controller design, one wait state was removed from many of the frame buffer access cycles. This results in reduced memory access time overall, and therefore improved performance. The graphics tests in Speedometer (version 3.11) show an improvement of roughly 6-10% over the earlier Quadra machines (each running System 7.1).
Basically, the Centris 610/650 and Quadra 800 support any display, whether from Apple or from another vendor, that meets one of the following specifications:
STANDARD SENSE CODES:
Sense pins Hor x Vert Dot Vert Horiz
Display 10 7 4 Pixels Clock Refrsh Refrsh
----------- ----------- ---------- ----- ------ ------
Apple 21S Color 0 0 0 1152 x 870 100 75 68.7
Apple Portrait 0 0 1 640 x 870 57.2832 75 68.9
12" Apple RGB 0 1 0 512 x 384 15.6672 60.15 24.48
Apple Two-Page Mono. 0 1 1 1152 x 870 100 75 68.7
NTSC 1 0 0 underscan-512x384 12.2727 59.94 15.7
1 0 0 overscan- 640x480 12.2727 59.94 15.7
(To produce a color NTSC signal, a RGB-to-NTSC converter is required.)
12" AppleMonochrome 1 1 0 640 x 480 30.24 66.7 35.0
13" Apple RGB 1 1 0 640 x 480 30.24 66.7 35.0
Extended sense codes will be examined if the following sense code is
detected:
1 1 1
NOTE 1 on above monitors: A sense pin value of 0 means that the pin
should be grounded to the C&V SYNC.GND signal; a value of 1 means do
not connect the pin.
NOTE 2 on above monitors: sense pins 4, 7, and 10 are referred to as SENSE0, SENSE1, and SENSE2 in pinout tables for the video connectors.
NOTE 3: The terms 'underscan' and 'overscan' are used to describe the active video resolution for NTSC and PAL modes. Underscan means that the active video area appears in a rectangle centered on the screen with a black surrounding area. This ensures that the entire active video area always is displayed on all monitors. Overscan utilizes the entire possible video area for NTSC or PAL. However, most monitors or televisions will cause some of this video to be lost beyond the edges of the display, so the entire image will not be seen.
EXTENDED SENSE CODES:
NOTE for extended sense codes: A sense pin pair value of 0 means those pins should be tied together (as opposed to grounding the pins to pin 11); a value of 1 means do not connect the pins. Do _not_ wire any of these pins to ground.
Sense pins Hor x Vert Dot Vert Horiz
Display 4-10 10-7 7-4 Pixels Clock Refrsh Refrsh
----------- ------------- ---------- ----- ------ ------
16" Color 0 1 1 832 x 624 57.2832 75 49.7
PAL
PAL has two wiring options, using the extended sense pin configuration.
To produce a color PAL signal, an RGB-to-PAL converter is required.
PAL Option 1 0 0 0 underscan-640x480 14.75 50 15.625
overscan-768x576 14.75 50 15.625
PAL Option 2 1 1 0 underscan-640x480 14.75 50 15.625
overscan-768x576 14.75 50 15.625
Note: This sense code also requires a diode between sense pins 10 & 7,
with anode towards pin 7, cathode towards pin 10.
VGA 1 0 1 640 x 480 25.175 59.95 31.47
SVGA 1 0 1 800 x 600 36 56 35.16
To enable SVGA, after configuring and connecting the monitor for VGA, open
the Monitors control panel and select Options. Choose Super VGA from the
dialog and reboot your system.
19" Color 1 1 0 1024 x 768 80 75 60.24
No external monitor (video halted)
1 1 1
Here are the video connector pinouts:
Pin Signal Description ----- ----------- ---------------------------------------- 1 RED.GND Red Video Ground 2 RED.VID Red Video 3 CYSNC~ Composite Sync 4 MON.ID1 Monitor ID, Bit 1 (also known as SENSE0) 5 GRN.VID Green Video 6 GRN.GND Green Video Ground 7 MON.ID2 Monitor ID, Bit 2 (also known as SENSE1) 8 nc (no connection) 9 BLU.VID Blue Video 10 MON.ID3 Monitor ID, Bit 3 (also known as SENSE2) 11 C&V SYNC.GND CSYNC & VSYNC Ground 12 VSYNC~ Vertical Sync 13 BLU.GND Blue Video Ground 14 HSYNC.GND HSYNC Ground 15 HSYNC~ Horizontal Sync Shell CHASSIS.GND Chassis GroundIf your monitor is a VGA type, you can try the following cable pinouts.
Macintosh Video VGA Connector DB-15 ------------- -------------- 2 ------------------- Red Video ------------ 1 1 ------------------- Red Ground ----------- 6 9 ------------------- Blue Video ----------- 3 13 ------------------- Blue Ground ---------- 8 5 ------------------- Green Video ---------- 2 6 ------------------- Green Ground --------- 7 15 ------------------- Hsync ---------------- 13 12 ------------------- Vsync ---------------- 14 14 ------------------- Sync Ground ---------- 10 10 ------------------| 7 ------------------| Connect 7 and 10 so the sense pin ID will equal VGA
There are a few issues to keep in mind with VGA monitors:
Most NTSC devices use an RCA-type phono-connector and the following diagram uses that as a reference point. A cable wired as follows may allow many different brands of NTSC monitors to work on a Macintosh Centris or Quadra. I would advise you to test the monitor on one of these machines prior to purchase to see if it meets your expectations.
Adjust the phono-connector side to whatever type of connector is used (RCA, BNC, etc.). "Tip" is the pin in the center of the connector (the signal); the sleeve is flange around the outer edges of the connector (the chassis ground).
Card Connector RCA-Type Phono-Connector -------------- ------------------------ 4 MON.ID1 (sense0) --| 7 MON.ID2 (sense1) --| 11 C&V SYNC.GND --------| 5 GRN.VID -----------------> Tip (signal) Shell CHASSIS.GND --------------> Sleeve (ground)By grounding pin 4 and pin 7 to pin 11, the Macintosh Centris and Quadra CPUs are told that an NTSC monitor is attached. The actual black and white video signal is on pin 5 and connects to the center (Tip) of the phono-plug. The shell of the card connector connects to the sleeve of the phono-plug.
To acquire a color NTSC signal from a Centris or Quadra (or any Apple Macintosh display card), an RGB-to-composite video converter is required.
The following chart lists the Centris 610/650 and Quadra 800 built-in video's maximum pixel depth supported depending upon the VRAM configuration:
Display size 512K VRAM 1MB VRAM ----------------- --------- -------- 12-inch landscape 384 x 512 16 bpp 16 bpp 12-inch Monochrome 640 x 480 8 bpp 8 bpp 13-inch RGB & VGA 640 x 480 8 bpp 16 bpp SVGA 800 x 600 8 bpp 16 bpp 15-inch Portrait (b/w) 640 x 870 4 bpp 8 bpp 16" Color, 832 x 624 8 bpp 16 bpp 19" Color, 1024 x 768 4 bpp 8 bpp 2-Page Display (b/w) 1152 x 870 4 bpp 8 bpp 21" Color 1152 x 870 4 bpp 8 bpp PAL underscan-640x480 8 bpp 16 bpp overscan-768x576 8 bpp 16 bpp NTSC underscan-512x384 8 bpp 16 bpp overscan- 640x480 8 bpp 16 bpp- Dale Adams
November 16, 1993 - Robert Lentz
(ralentz@ralentz.com)
