83:Ports:02

From WikiTI
Revision as of 02:25, 30 March 2005 by 195.56.94.159 (Talk)

Jump to: navigation, search

Synopsis

Port Number: 02h

Function: ROM and RAM Pager

This port controls what page is swapped into the 4000h to 7FFFh range.

Read Values

Always the last value output is read back.

Write Values

  • Bits 0 to 2: The lower 3 bits of the desired ROM page (bit 3 can be set through bit 4 of the link port)
  • Bit 3: Must be 1, otherwise the the calculator crashes
  • Bit 4: 0 - the specified ROM page is swapped in, 1 - the RAM page specified by bit 0 swapped in (0 causes it to mirror the page at C000h, 1 mirrors the page at 8000h)
  • Bit 5: Unknown, harmless
  • Bit 6: Unknown, harmless
  • Bit 7: Must be 1, otherwise the the calculator crashes

Credits and Contributions

  • created by CoBB