TFROM: Difference between revisions

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(→‎Solder Pad Config: To do: determine which is which)
(see http://kevtris.org/mappers/mmc3/NES_TFROM.html - pad CL2 is connected directly to cart edge pin 15 (which is /IRQ), while CL1 is right next to H and V)
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== Solder pad configuration ==
== Solder pad configuration ==
* Normal mode : 'CL1' connected, 'CL2' connected, 'H' disconnected, 'V' disconnected.
* Normal mode : 'CL1' connected, 'H' disconnected, 'V' disconnected, 'CL2' connected.
* [[DEROM]] backward compatibility mode with Horizontal mirroring : 'CL1' disconnected, 'CL2' disconnected, 'H' disconnected, 'V' connected.
* [[DEROM]] backward compatibility mode with Horizontal mirroring : 'CL1' disconnected, 'H' disconnected, 'V' connected, 'CL2' disconnected.
* DEROM backward compatibility mode with Vertical mirroring : 'CL1' disconnected, 'CL2' disconnected, 'H' connected, 'V' disconnected.
* DEROM backward compatibility mode with Vertical mirroring : 'CL1' disconnected, 'H' connected, 'V' disconnected, 'CL2' disconnected.


Note : In DEROM backward compatibility mode, mirroring is hardwired and IRQs are disabled. However, the additional bank switching modes available by the MMC3 that weren't available with the MIMIC-1 chip used on DEROM boards are still present.
Note : In DEROM backward compatibility mode, mirroring is hardwired and IRQs are disabled. However, the additional bank switching modes available by the MMC3 that weren't available with the MIMIC-1 chip used on DEROM boards are still present.


''To do:'' determine which of CL1 and CL2 affects the IRQ and which affects mirroring.
Connecting 'CL1' enables MMC3-controlled mirroring, while connecting 'CL2' enables IRQs.


== See also ==
== See also ==
*[[MMC3|Nintendo MMC3]]
*[[MMC3|Nintendo MMC3]]

Revision as of 21:28, 11 February 2010

TFROM (NES-TFROM and HVC-TFROM) is a common board within the TxROM set. Like other TxROM boards, TFROM uses the Nintendo MMC3 ASIC.

Overview

  • PRG ROM size: 128, 256 or 512 KB (DIP-28/32 Nintendo pinout)
  • PRG ROM bank size: 8 KB
  • PRG RAM: None
  • CHR capacity: 32 or 64 KB ROM (DIP-28 standard pinout)
  • CHR bank size: 1 KB and 2 KB
  • Nametable mirroring: Solder pads select horizontal, vertical or controlled by mapper.
  • Subject to bus conflicts: No

Solder pad configuration

  • Normal mode : 'CL1' connected, 'H' disconnected, 'V' disconnected, 'CL2' connected.
  • DEROM backward compatibility mode with Horizontal mirroring : 'CL1' disconnected, 'H' disconnected, 'V' connected, 'CL2' disconnected.
  • DEROM backward compatibility mode with Vertical mirroring : 'CL1' disconnected, 'H' connected, 'V' disconnected, 'CL2' disconnected.

Note : In DEROM backward compatibility mode, mirroring is hardwired and IRQs are disabled. However, the additional bank switching modes available by the MMC3 that weren't available with the MIMIC-1 chip used on DEROM boards are still present.

Connecting 'CL1' enables MMC3-controlled mirroring, while connecting 'CL2' enables IRQs.

See also