hr@uicsl.UUCP (03/07/86)
<>
A question about the Sun 3/160C.
Could someone tell me if (how) one can synchronize a procedure
to the vertical retrace? Is there a signal available or is there
a status register bit we could check?
----
harold ravlin {ihnp4,pur-ee}!uiucdcs!uicsl!hrchris@umcp-cs.UUCP (Chris Torek) (03/13/86)
I do not know about the 3s, but the Sun 2 video registers do not seem to include a vertical retrace bit. -- In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 1415) UUCP: seismo!umcp-cs!chris CSNet: chris@umcp-cs ARPA: chris@mimsy.umd.edu
david@sun.uucp (David DiGiacomo) (03/14/86)
In article <7300003@uicsl> hr@uicsl.UUCP writes: >A question about the Sun 3/160C. >Could someone tell me if (how) one can synchronize a procedure >to the vertical retrace? Is there a signal available or is there >a status register bit we could check? The current color frame buffer (cg2) is described in the "Hardware Reference Manual for the Sun-2 Color Graphics Board", part number 800-1189-01. Section 2.8 covers the status register, including the retrace bit. You could also look at the cg2statusreg struct in <pixrect/cg2reg.h>. There is also a vertical retrace interrupt, which is not used by the current kernel driver. P.S. I think this is the wrong newsgroup. -- David DiGiacomo {decvax, ihnp4, ucbvax}!sun!david david@sun.arpa Sun Microsystems, Mt. View, CA (415) 960-7495
henry@utzoo.UUCP (Henry Spencer) (03/16/86)
>There is also a vertical retrace interrupt, which is not used by the current >kernel driver. If the current software doesn't use it, be sure it works before you rely on it! This may sound a bit silly, but it's not -- a friend of mine who worked with some of the very early commercial Suns discovered, as I recall, that the vertical-retrace interrupt on the Sun 1 (or maybe Sun 0.9) in fact did not work, and it turned out that Sun had never tried using it. -- Henry Spencer @ U of Toronto Zoology {allegra,ihnp4,linus,decvax}!utzoo!henry
gnu@hoptoad.uucp (John Gilmore) (03/18/86)
In article <6518@utzoo.UUCP>, henry@utzoo.UUCP (Henry Spencer) writes: > If the current software doesn't use it, be sure it works before you rely > on it! This may sound a bit silly, but it's not -- a friend of mine who > worked with some of the very early commercial Suns discovered, as I recall, > that the vertical-retrace interrupt on the Sun 1 (or maybe Sun 0.9) in fact > did not work, and it turned out that Sun had never tried using it. Actually, this is not quite true. I diagnosed that problem. The Sun-1 Multibus video board had a 3-bit field which specified the interrupt level on which it was supposed to interrupt. (A value of 000 would suppress the interrupt.) It turns out that these bits were inverted before being used as an interrupt level. Thus a value of 000 specifies an interrupt on level 7, 001 is level 6, ... 111 suppresses the interrupt. This was discovered about 2 years after the product was in the field. I discovered it because I noticed a software bug in the terminal emulator which this hardware bug was masking. At the time I recommended that the "fix" be a documentation change; since only a few customers were likely to be affected, there was no sense ECO-ing the board. I believe the diagnostics for the Sun-2 and Sun-3 color boards test the video retrace interrupt. Can we move further discussion (if any) to Sun-Spots (mod.computers.sun)? -- John Gilmore {sun,ptsfa,lll-crg,ihnp4}!hoptoad!gnu jgilmore@lll-crg.arpa Post no bills.