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  • Re: Dude looked like a lady [fooling MCGA w/ non-Monitor Sense displays

    From Louis Ohland@21:1/5 to Louis Ohland on Sat Mar 5 09:43:16 2022
    https://ardent-tool.com/docs/pdf/PS2_Model_25_Technical_Reference_Jun87.pdf#page=49

    Page 65 physical

    Display Sense Register, Index 12: This register contains the sensed
    levels of the monitor sense 1 and 0 signals at pins 13 and 14 of the
    display connector [HDD15]. This information is used by BIOS to properly initialize all video registers to match the display.

    Figure 1-41 Monitor Sense Bits

    MS1 MS0 Type of Display Attached
    0 0 Reserved
    0 1 Analog Monochrome Display
    1 0 Analog Color Display
    1 1 No Display Attached

    0 = Shunt
    1 = Open

    So, if my years of advanced hedonism haven't totally destroyed too many
    brain cells, we tie MS1 to GND and leave MS0 open.


    On 3/5/2022 09:28, Louis Ohland wrote:
    If modern displays lack a Monitor Sense pin[s] needed to enable 31kHz operation, can we add a pass-through HDD15-HDD15 dongle that works on
    MS0,1? Or, we could shunt the pins inside the system...

    Without the presence of Monitor Sense / Monitor ID, MCGA comes up in
    15kHz, something many displays do not support.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Tomas Slavotinek@21:1/5 to Louis Ohland on Sat Mar 5 21:46:16 2022
    Yep this is the digital monitor ID I was talking about. The EXT V/EXT H
    stuff in the schematic is BS... once again.

    On 05.03.2022 16:43, Louis Ohland wrote:
    https://ardent-tool.com/docs/pdf/PS2_Model_25_Technical_Reference_Jun87.pdf#page=49


    Page 65 physical

    Display Sense Register, Index 12: This register contains the sensed
    levels of the monitor sense 1 and 0 signals at pins 13 and 14 of the
    display connector [HDD15]. This information is used by BIOS to properly initialize all video registers to match the display.

    Figure 1-41 Monitor Sense Bits

    MS1  MS0 Type of Display Attached
     0    0  Reserved
     0    1  Analog Monochrome Display
     1    0  Analog Color Display
     1    1  No Display Attached

    0 = Shunt
    1 = Open

    So, if my years of advanced hedonism haven't totally destroyed too many
    brain cells, we tie MS1 to GND and leave MS0 open.


    On 3/5/2022 09:28, Louis Ohland wrote:
    If modern displays lack a Monitor Sense pin[s] needed to enable 31kHz
    operation, can we add a pass-through HDD15-HDD15 dongle that works on
    MS0,1? Or, we could shunt the pins inside the system...

    Without the presence of Monitor Sense / Monitor ID, MCGA comes up in
    15kHz, something many displays do not support.


    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)