OCM_SM 3.9a - Release Candidate

OCM-PLD v3.9a

PLEASE DON'T USE THIS RELEASE, THE FULL RELEASE IS AVAILABLE, IT IS KEPT HERE FOR HISTORY REASONS.
CHECK FOR OCM_SM 3.9a - Oficial Release instead.

OCM-PLD v3.9a is an extension on KdL OCM release v3.9. What this extension
brings to the table:

• For regular SM-X, SM-X mini and SX-2:

  • Fix: I've fixed OPL3, it had two issues that prevented it to work with
    the latest VGMPlay version:

    • IRQ was not connected, so timers programmed wouldn't trigger,
      instead only the VDP interrupt, to slow, so music would play darn
      slow with VGMPlay.

    • Even after fixing that, playing speed was almost half of the correct
      speed for VGMs. The timer scaler was not properly set causing it to
      trigger slower than programmed.

    Since VGMPlay 1.3 relies on OPL3 timer when present to drive a high speed
    interrupt, not having IRQ and not having the proper scaler for timer
    caused its timing to be slow, darn slow...

  • Fix: I've fixed OPL3 sound rendering as it was discarding all information
    that is on right output channel only, unfortunately we do not have enough
    FPGA resources to run the sequencer for two channels, but a clever trick
    allow all songs content to be properly played in MONO glory :P Try as an
    example Doom soundtrack track 3 before updating and after updating it. :)

• Adds support to SMX-HB (as it has only initial support for OCM 3.7.1)

  • Extra: I've allowed Joystick port debounce to be disabled, this perhaps
    can alleviate the issues some users were having with paddles. To turn off
    Joystick port debounce use the command SETSMART -89 , to turn it back on
    use the command SETSMART -8A , power cycle will restore default, on.

  • Extra: I've added support to different keyboard map tables. This is handy
    as the internal keyboard of Hotbit is not standard and its map is very
    peculiar, while PS/2 keyboards have a different mapping. DIP switch 9 set
    to OFF is the default, using the internal mapping, if set to ON it will
    use the mapping the firmware was built-in, that is handy when you want to
    use an external keyboard.

  • Fix: Select key was not working on original 3.7.1 based release, it works
    now. Also, SELECT + UP and SELECT + DOWN replaces Page Up and Page Down,
    so it is possible to activate the autofire module using only SMX-HB
    internal keyboard.

  • Missing: SMX-HB FPGA has less cells than other SM-X devices as it uses
    a FPGA with about 70% of the capacity of the other devices, so it doesn't
    support OPL3 as it won't fit

• Adds to regular SMX-HB, SM-X, SM-X mini and SX-2 a frankysnd build:

  • Extra: I've added partial support to a built-in Franky. That partial
    support is good enough to work with SG1000, COL4MMM (using COM\Franky
    versions) VGMPLAY and Sofarun (remember to set it to use MSX VDP and
    Franky's PSG). As Franky sound uses I/O ports 0x48 and 0x49, and those
    ports are part of the switched I/O, it is usually disabled, as OCM IPL
    loader will leave switched I/O selected after booting. There are
    different ways to enable Franky sound:

    • VGMPLAY will automatically disable switched I/O, so you can play a
      VGM song that uses SN76489 and after exiting VGMPLAY you can use other
      software.

    • De-select the internal switched I/O by sending the basic command
      OUT &H40,0

    • Use SETSMART -8C to enable the I/O ports 0x48 and 0x49 for that, so
      any program relying on reading OCM information on those ports won't
      get it.

• Planned for the future SM-X, SM-X mini and SX-2 will have a franky build:

  • Missing: FPGA in those devices can't fit OPL3 along with Franky VDP and
    PSG, so that build won't have OPL3 support.

  • Extra: this is a WIP, please wait, but it will have Franky VDP :P

How to choose the firmware?

1 - Obviously, you will download the one for your device. (i.e.: I have a SM-X,
so I get firmware files from folders that start with smx_)

2 - Next step is to find out if you want vanilla or Franky Sound version. If
you don't own a Franky cartridge or a Playsoniq cartridge, go ahead with the
Franky Sound version. If you have one of those two interfaces, a Franky or
Franky Sound version will conflict with your cartridge, so it is best to stick
with a vanilla version. (Vanilla means nothing after the device name)

3 - (FUTURE ONLY, NOT NOW) You've found out that your 2nd Gen device has
support for a FrankyFull version. If in 2 you would choose Franky Sound, then
seems like choosing FrankyFull (that has Master System VDP support) would be a
no brainer, right? Wrong... Unfortunately it is not possible to fit Master
System VDP / CRAM / VRAM along with OPL3. So if you like VGMPLAY and use it to
play OPL3 VGMs or have other uses for OPL3, you may prefer to use Franky Sound
version instead.

4 - WOW! That folder contains 16 different firmware files!!! I have no idea how
to choose from...

- Do not worry, first, let's get down to four different files, you do this
by figuring out your PS/2 Keyboard Layout, French, Spanish, Brazilian or
US. IMPORTANT: SD-BIOS DO NOT CHANGE Keyboard Layout, so it is important
to choose the correct one :)
- Now, you have four different versions, let's get down to two. Do you
prefer backslash symbol to be shown as a real backslash or do you prefer a
it to be shown as the yen symbol like japanese MSX's? Based on that, choose
yen or backslash. If you use SD-BIOS, then this is not relevant as the
SD-BIOS will override whatever is flashed in that regards
- Finally, you will have SINGLE EPBIOS or DUAL EPBIOS. On DUAL EPBIOS, if
you do not use a SD-BIOS, you can easily switch between Nextor or MSX Dos 2
kernel by flicking dip-switch 7. In the position for 4096 MB Mapper it will
use Nextor Kernel (this change needs turning the device off and then on to
take effect), in the position for 2048 MB Mapper it will use MSX Dos 2
Kernel. Single EPBIOS use only MSX Dos 2 Kernel. If you use SD-BIOS, then
this is not relevant as the SD-BIOS will override whatever is flashed in
that regards

5 - Now you have your firmware file, just use it :)

All source code that changed in relation to OCM 3.9 and binaries:
(c)2022 Oduvaldo Pavan Junior - ducasp@gmail.com

All source code from OCM 3.9 originally is a work of many people, including
KdL and Hara-san that are really huge contributors to it!

All code can be re-used, re-written, derivative work can be sold, as long as the
source code of changes is made public as well.