List of Errata and Addenda

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[edit] Elf 2000 Main Board

  • DS1210 VBAT2 grounding issue
On the Elk2K main board, chip U5, the DS1210, MUST have pin 7, VBAT2, tied to ground (Pin 4).
DS1210 datasheet PDF:
  • V87 Firmware - RUN Command Issue
The monitor's RUN command always executes code beginning at 0000; any parameter is ignored. The code at RUNUSR checks for the Elf 2000 video board as a first step. The idea is that if the card is in use with interrupts and DMA going on, there's no way to use R0 as a program counter, so the RUN command detects this and bails if needed. Unfortunately, the test for the video card at ISCRTC trashes P1 (register F) as a side effect, and P1 is the command line pointer. The test leaves P1 pointing to VIDVER, which will be 00 if no video card is present. When the code returns back to the RUNUSR block ISEOL gets called, which now looks at the 00 at VIDVER and concludes the end of line has been reached.
This has been fixed in v88 of the firmware,
  • V87 Firmware - Minor Attribution Error
The monitor's TEST PIXIE function prints text attributing the displayed test pattern to "Joeseph Weisberger"; the correct spelling should be "Joseph Weisbecker."

[edit] STG1861 Board

[edit] Disk/UART/RTC/NVR Board

  • There is a minor errata on the Disk/UART/RTC/NVR Board. On U7, the 16C450 UART, pin 36 /CTS is an input which is not connected to anything. As far as I can tell from the datasheet this IC does not have pullups fitted so this pin should be connected to something. On my board I have run a wire from /RTS pin 32 to /CTS pin 36.

[edit] Hexadecimal Keypad

  • In the Elf 2K manual, 6th Edtion dated 10/1/2006 4:23 PM, there is an IC missing from the parts list for the Hex keypad - U5 a CD4001 (a quad 2 input NOR gate IC) needs to be added. Also U1 is a 74C922 not "74C9222" as in the parts list.

[edit] Operational Notes

  • The monitor's RUN command will start program execution with interrupts disabled. Since the 1802's reset state turns on interrupts, some programs may be written to expect interrupts enabled. Such programs may be modified to turn on interrupts using the 1802's RET instruction (opcode 0x70). See the discussion thread at

Elf 2000 Main Page

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