Groups > comp.sys.apple2.programmer > #120

Re: Converting HGR to DHGR

From	Jerry <awanderin@yahoo.ca>
Newsgroups	comp.sys.apple2.programmer
Subject	Re: Converting HGR to DHGR
Date	2012-01-21 02:53 -0700
Organization	bbs-scene usenet news
Message-ID	<m3wr8lwfd7.fsf@yahoo.ca> (permalink)
References	(2 earlier) <0c35bd21-7af2-41b1-a96e-fbd69aa33442@t8g2000yqg.googlegroups.com> <alpine.DEB.2.00.1201181105020.20679@zztop.nucleusys.com> <892a42af-44e2-4170-8f2a-8cd606e8c809@u2g2000vbe.googlegroups.com> <6055580d-a21b-49d3-b82b-57414beeff21@b20g2000yqb.googlegroups.com> <alpine.DEB.2.00.1201191310360.11945@zztop.nucleusys.com>

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Vladimir Ivanov <vladitx@XXXyahooXXX.com> writes:

> On Wed, 18 Jan 2012, BLuRry wrote:
>
>> 1 bit shift for DHGR though??
>
> Not likely. If you have setup with color monitor just try it.

80-column mode, and DHGR actually starts seven bits (14.318180 MHz
periods) sooner (one 80-column character width) than 40-column mode,
which explains the shift in colors if either you don't do the shift to
compensate, or you don't simulate the whole dot stream coming out of the
shift registers.

Try this on a IIe or IIc to see the effect:

1 D = 500
2  PR# 3: PRINT " "
5  GOTO 100
10  PRINT  CHR$ (17);
20  FOR X = 1 to D: NEXT
30  PRINT  CHR$ (18);
40  FOR X = 1 to D: NEXT
50  GOTO 10
100  HGR : POKE 49246,0
101  DATA 160,0,132,0,162,32,134,1,141,84,192,177,0,141,85,192,145,0,200
    ,208,243,230,1,202,208,238,96
102  FOR A = 768 TO 794: READ X: POKE A,X: NEXT
110  HCOLOR= 3: HPLOT 0,0: CALL 62454
120  GOTO 10

You will see the left and right borders moving left and right a bit as
the display switches from 80 columns to 40 columns and back.

-- 
--
Jerry    awanderin at yahoo dot ca

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Thread

Converting HGR to DHGR BLuRry <brendan.robert@gmail.com> - 2012-01-17 07:32 -0800
  Re: Converting HGR to DHGR Vladimir Ivanov <vladitx@XXXyahooXXX.com> - 2012-01-17 18:20 +0200
    Re: Converting HGR to DHGR Antoine Vignau <antoine.vignau@laposte.net> - 2012-01-17 09:10 -0800
    Re: Converting HGR to DHGR BLuRry <brendan.robert@gmail.com> - 2012-01-17 09:26 -0800
      Re: Converting HGR to DHGR Vladimir Ivanov <vladitx@XXXyahooXXX.com> - 2012-01-18 11:17 +0200
        Re: Converting HGR to DHGR BLuRry <brendan.robert@gmail.com> - 2012-01-18 11:04 -0800
          Re: Converting HGR to DHGR BLuRry <brendan.robert@gmail.com> - 2012-01-18 20:34 -0800
            Re: Converting HGR to DHGR Vladimir Ivanov <vladitx@XXXyahooXXX.com> - 2012-01-19 13:12 +0200
              Re: Converting HGR to DHGR Jerry <awanderin@yahoo.ca> - 2012-01-21 02:53 -0700
                Re: Converting HGR to DHGR Vladimir Ivanov <vladitx@XXXyahooXXX.com> - 2012-01-21 18:48 +0200
                Re: Converting HGR to DHGR Daniel Kruszyna <dan@krue.net> - 2012-02-18 20:58 +0000
                Re: Converting HGR to DHGR BLuRry <brendan.robert@gmail.com> - 2012-02-18 15:00 -0800
  Re: Converting HGR to DHGR "ict@ccess" <gids.rs@sasktel.net> - 2012-02-19 19:05 -0800

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