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F18A 30 rows/80 character mode?

F18A

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#1 retroclouds OFFLINE  

retroclouds

    Stargunner

  • 1,662 posts
  • Location:Germany

Posted Sun Dec 2, 2018 1:23 PM

Think I read somewhere that the F18A also supports a 30 rows/80 character mode as opposed to the "normal" 24 x 80 columns mode.

If that is true, can someone point me how the F18A VDP registers must be set to activate the mode?

 

Thanks

retroclouds

 

*EDIT* It's 30 rows, not 31 rows.



#2 PeteE OFFLINE  

PeteE

    Chopper Commander

  • 170 posts
  • Location:Beaverton, OR

Posted Sun Dec 2, 2018 2:13 PM

The ROW30 flag is in register VR49.  I have crudely made the register layout here:

         +----------+--------+-------+-------+--------+-------+-------+-------+
VR49 >31 | TILE2_EN | ROW30  | ECMT0   ECMT1 | Y_REAL | LINK  | ECMS0   ECMS1 |
         +----------+--------+-------+-------+--------+-------+-------+-------+
           Tile map 2 enable   ECM (T)ile      real sprite Y coord   ECM (S)prite
                      24/30 tile rows                   Sprite linking enable


#3 matthew180 OFFLINE  

matthew180

    River Patroller

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  • Location:Castaic, California

Posted Sun Dec 2, 2018 6:59 PM

You can thank the NES for the 30-row support (and a few other enhancements).  Keep in mind that when all 30-rows are enabled, the name tables are larger.  Pixel scrolling is also available in T80 mode, but not the multiple pages.  Unlock the F18A and set bit >40 in VR49 (as shown above, thanks PeteE), and you will have 30-rows available.  The Text modes also have the "position-based attributes" available.

 

Note that in the next F18A firmware (yes, there is going to be at least one more, if not two, updates), Sprite Linking and the Real Sprite Y position features are going away.  I only mention those here because they are part of VR49.



#4 --- Ω --- OFFLINE  

--- Ω ---

    HexaCoreRunner

  • 13,147 posts

Posted Sun Dec 2, 2018 7:05 PM

 

Sprite Linking and the Real Sprite Y position features are going away. 

 

Have any programs even used them?



#5 OLD CS1 OFFLINE  

OLD CS1

    Technomancer

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Posted Sun Dec 2, 2018 7:33 PM

The 30 row mode is good news for reasons.



#6 matthew180 OFFLINE  

matthew180

    River Patroller

  • 2,565 posts
  • Location:Castaic, California

Posted Sun Dec 2, 2018 8:32 PM

 

Have any programs even used them?

 

Not AFAIK, which is not really definitive I know.  The reason for the change it technical and I needed to remove something to get FPGA resource utilization below 99%.  It is common for software that uses multiple spites (like games) keep a copy of the sprite table in CPU RAM and just overwrite the whole table in VRAM when a sprite needs to be updated.



#7 matthew180 OFFLINE  

matthew180

    River Patroller

  • 2,565 posts
  • Location:Castaic, California

Posted Sun Dec 2, 2018 8:33 PM

The 30 row mode is good news for reasons.

 

News? It has been there since the original release in 2012. ;-)



#8 OLD CS1 OFFLINE  

OLD CS1

    Technomancer

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  • Location:Tallahassee, FL

Posted Sun Dec 2, 2018 8:48 PM

 

News? It has been there since the original release in 2012. ;-)

 

Sadly been low-priority for me.







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