emu48-mirror/PROBLEMS.TXT

Known bugs and restrictions of Emu48 V1.40
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- the following I/O bits aren't emulated (incomplete)
  DTEST   (0x102) [VDIG LID TRIM]
  DSPCTL  (0x103) [LRT LRTD LRTC BIN]
  LPD     (0x108) [LB2 LB1 LB0 VLBI]
  LPE     (0x109) [ELBI EVLBI GRST RST]
  CMODE   (0x10A) Mode register
  IOC     (0x110) [ERBZ]
  RCS     (0x111) [RX RER RBZ]
  SRQ1    (0x118) [ISQR VSRQ]
  SRQ2    (0x119) [LSRQ]
  IRC     (0x11A) [IRI EIRU EIRI IRE]
  LCR     (0x11C) [LED ELBE LBZ LBF]
  LBR     (0x11D) [LBO]
- the baudrates 1920, 3840, 7680 and 15360 aren't emulated on most
  operating systems
  Windows 95a         1920, 3840, 7680 work, 15360 fail
  Windows 98          all baudrates fail
  Windows NT4.0 SP3   all baudrates fail
- problems when receiving a break signal on the serial port
  Windows 98, NT4.0 SP4 no retrigger on port open
  Windows 98 timing problems setting the RER bit
  Windows 2000 SP2 no known problems
- System-RPL commands VERYVERYSLOW, VERYSLOW and SLOW depends on PC
  speed (are realized as simple down counter in ROM)
- display updating differs from the real machine
- screen VBL counter values may skip after large display operations
  like turning on or updating the whole display
- executing an opcode over a MMU boundary will fail
- read on an unconfigured address (open data bus) will not show the
  same value like a real calculator
- the Yorke hardware signals BEN and DA19 aren't fully supported,
  because the emulator don't use a multiplexed AR18 / NCE3 data line
  -> all programs that run on a real calculator will run as well,
  programs with incorrect DA19 / BEN handling may run on the
  emulator but will crash on a real calculator
- incomplete reset logic of the bank switcher FF, on real
  calculators a reset happen after about 4s in deep sleep, in the
  emulator this happens immediately
- no MP interrupt on card control circuit or timer restart
- no beeper support with OUT command -> all programs that aren't
  use the "=makebeep" subroutine, like alarm wake up, have no sound
- beeper emulation, ATTN key doesn't work
- no infrared printer support
- Shell OS: clock isn't synchronized with real time
- HP49G: the flash memory is emulated now with some restrictions
  - no flash programming times, the flash state machine returns
    immediately the ready signal
  - only one write buffer, second not needed because of prior reason
  - not fully tested, especially the status byte may return
    incorrect values (error bits)
  - quitting the emulator while programming the flash isn't allowed,
    because the content of flash state machine isn't saved so far

12/13/05 (c) by Christoph Gie<69>elink, c dot giesselink at gmx dot de