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1335RE: [cosmacelf] Re: Programming Help

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  • William Waters
    Sep 1, 2003

      First off I must say thanks so very much for the help.

      I spent the afternoon experimenting with the code you sent. For whatever
      reason I had a few problems getting it to work, but came up with the below
      solution that seams to work just fine.

      I added the following:

      FFC0 F8 C7 A3 ; set up R3
      FFC3 F8 FF B3 ;
      FFC6 D3 ; set R3 as PC
      FFC7 3F ; wait for In press
      FFC8 C7
      FFC9 37 ; wait for In release
      FFCA C9
      FFCB 30 D3 ; jump to program
      FFD3 7B ; set Q for Effect
      Added 2 additional FE (shl) in the loop such that the program moves only 4K
      into RAM (this should work, right???).
      Added 7A 00 ; Clear Q and just sit there

      A cycle of the 'RUN' switch and the program is at 0x0000 ready to run.

      So far I have tested the Netronics Tiny Basic and TMSI Tiny Basic and both
      relocate down to RAM and both Run Fine.

      All I have to work with are the document "A Short Course in Programming" by
      Tom Pittman, an original blue RCA 1800 Instruction Summary card, and source
      listings of various programs. The programming Guide to the 1802 sure would
      be handy. I have spent many years writing assembly code for the Zilog Z8
      microcontroller family, but the 1802 is quite a bit different.

      To answer your question, my EPROM program is a Needham's Electronics EMP-20,
      and the Emulator is an ER3 EconoRom-III by Tech-Tools.

      I will continue 'tinkering' with your move program and get my final EPROM
      loaded with the applications next.

      Thanks again!!!

      -----Original Message-----
      From: joshbensadon [mailto:joshbensadon@...]
      Sent: Monday, September 01, 2003 7:51 AM
      To: cosmacelf@yahoogroups.com
      Subject: [cosmacelf] Re: Programming Help


      > I then attempted placing a small patch of code at 0xF4F0 to set the
      > counter to R3 as the program assumes it to be already set. I would
      > execute the program by jumping to F4F0 from the Monitor ROM.
      > F4F0 F8 F4 A3 R3.0 = F4
      > F4F3 F8 F0 B3 R3.1 = F0
      > F4F6 D3 PC = R3

      This code will branch you to 0xF0F4, is that where you want to go?
      Where is this relocator?
      Here, try this code... I entered it in HEX, your favorite.
      It's the same code I posted earlier, except this time
      in machine language. It basically moves memory to ram until
      16k ram is full. It does not modify any code along the way.
      The table must start at xx00, but the stored programs can
      start at any location. Jump to FFE6 to run it.
      Change FFEA to any page to relocate this code.

      .org $FF00
      FF00 80 00 pgmtable .dw $8000 start of program 0
      FF02 82 00 .dw $8200 start of program 1
      FF04 86 45 .dw $8645 start of program 2
      ... etc

      .org $FFE6
      FFE6 6C inp 4
      FFE7 FE shl ;x2 for address words
      FFE8 AD plo rd ;Table must start at xx02
      FFE9 F8 FF ldi pgmtable/256 ;rD points to table
      FFEB BD phi rd

      ;set starting write address
      FFEC F8 00 ldi 0 ;Write to 0000
      FFEE AE plo rE
      FFEF BE phi rE ;rE points to destination

      FFF0 4D lda rd ;get address of first 2 pages
      FFF1 BC phi rc
      FFF2 4D lda rd
      FFF3 AC plo rc ;rC points to source

      FFF4 4C RRLoop lda rc ;read a source byte (and advance)
      FFF5 5E str rE ;write a destination byte
      FFF6 1E INC rE ;(and advance)
      FFF7 9E ghi rE ;Test for end of RAM
      FFF8 FE shl ;x2
      FFF9 FE shl ;x4 for 16K ram check
      FFFA 3B F4 bnf RRLoop
      FFFC C0 00 00 lbr 0000

      > The above did not seam to work either. I do not have original
      binary or any
      > better than what was in the .PDF.

      What are you programming your eeprom with?

      Good luck, the code is as small and simple as possible.

      Visit the COSMAC ELF website at http://www.cosmacelf.com, or view the
      Wiki/FAQ at http://1802.bitting.com/

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