| Platform | Resolution | Buffer | Remarks |
|---|---|---|---|
| MiST | 256x64 | 2kB | |
| MiSTer | 256x128 | 4kB | HD mode +1kB |
In both cases, the buffer encodes pixel columns in bytes: each byte contains one 8-pixel row.
The macro JTFRAME_OSDCOLOR should be defined with a 6-bit value encoding an RGB tone. This is used for the OSD background. The meanins are:
| Value | Meaning | Colour |
|---|---|---|
| 6'h3f | Mature core | Gray |
| 6'h1e | Almost done | Green |
| 6'h3c | Playable with problems | Yellow |
| 6'h35 | Very early core | Red |
To disable support of DIP switches in MRA files define the macro JTFRAME_NO_MRA_DIP. The maximum length of DIP switches is 32 bits. To alter the value of DIP switches in simulation use JTFRAME_SIM_DIPS.
In MiST, DIP switches are incorporated into the status word. As some bits in the status word are used for other OSD settings, DIP switches are by default located in range 31:16. This is set by the macro JTFRAME_MIST_DIPBASE, whose default value is 16. Note that the MRA should match this, the base attribute can be used in the MRA dip definition to shift the switch bits up.
| Macro | Effect |
|---|---|
| JTFRAME_SIM_DIPS | 32-bit value of DIPs used in simulation only |
| JTFRAME_OSD_NOLOAD | Do not display load file |
| JTFRAME_OSD_NOCREDITS | Do not display Credits |
| JTFRAME_OSD_FLIP | Display flip option (only for vertical games) |
| JTFRAME_OSD_NOSND | Do not display sound options |
Status bits in the configuration string are indicated with characters. This is the reference of the position for each character:
Bits 0-31 (o in upper case)
bit 00000000001111111112222222222233
number : 01234567890123456789012345678901
status char: 0123456789ABCDEFGHIJKLMNOPQRSTUV
Bits 32-63 (o in lower case)
bit 33333333444444444455555555556666
number : 23456789012345678901234567890123
status char: 0123456789ABCDEFGHIJKLMNOPQRSTUV
The status words are defined in the cfgstr files for each target. With the following encoding:
| 1st char | Meaning |
|---|---|
| Omn | option for bits 0-31. m character sets LSB, n sets MSB |
| o (lower) | same as O but for bits 32-63 |
| HnOm | Option code m, which can be hidden by hide bit n |
| DnOm | Option code m, which can be grayed out by hide bit n |
| J | Joystick definition |
| R | Reset |
| V | Core version |
MiST and MiSTer use 64-bit status words, but Neptuno and MC systems only have 32 bits.
| bit | meaning | Enabled with macro |
|---|---|---|
| 0 | Reset in MiST | |
| 1 | Flip screen | JTFRAME_VERTICAL && JTFRAME_OSD_FLIP |
| 2 | Rotate controls | JTFRAME_VERTICAL (MiST) |
| 2 | Rotate screen | JTFRAME_VERTICAL, visibility masked (MiSTer/Pocket) |
| 3-4 | Scan lines | Scan-line mode (MiST only) |
| 3-5 | Scandoubler Fx | Scan line mode and HQ2X enable (MiSTer only) |
| 6-7 | FX Volume (00=lowest) | JTFRAME_OSD_VOL |
| 6-7 | Spinner sensitivity | MiST cfgstr maps the spinner here, but jtframe_board always looks at 32-33 |
| 8 | FX enable/disable | JTFRAME_OSD_SND_EN |
| 9 | FM enable/disable | JTFRAME_OSD_SND_EN |
| 10 | Test mode | JTFRAME_OSD_TEST |
| 11 | Horizontal filter | MiSTer only |
| 12 | Credits/Pause | JTFRAME_OSD_NOCREDITS (disables it) |
| 13-15 | Reserved for core use | CORE_OSD (option char: D,E,F) |
| 16-17 | Aspect Ratio | MiSTer only, visibility masked |
| 18 | Autofire button 0 | JTFRAME_AUTOFIRE0 |
| 19 | 60 Hz option | JTFRAME_OSD60HZ %% |
| 32-33 | Spinner sensitivity | MiSTer only |
| 37-38 | User output options | MiSTer, selects DB15, UART, etc. |
| 39-40 | Rotate options (MiSTer) | JTFRAME_VERTICAL && JTFRAME_ROTATE (see below) |
| 41 | Vertical crop (MiSTer) | MiSTer only |
| 42-45 | Crop offset (MiSTer) | MiSTer only |
| 46-47 | Scaling style (MiSTer) | MiSTer only |
| 48 | CRT H scaling enable | MiSTer only |
| 49-52 | CRT H scaling factor | MiSTer only, visibility masked |
| 53-56 | CRT H offset | MiSTer only |
| 57-60 | CRT V offset | MiSTer only |
| 61-63 | Reserved for forks | JTFRAME forks can use these bits% |
Credits/Pause are handled differently in MiSTer vs MiST. For MiSTer, bit 12 sets whether credits will be displayed during pause. For MiST, bit 12 sets the pause. This difference is due to MiST missing key mapping, so I assume that MiST users depend more on the OSD for triggering the pause.
% JTFRAME will not expand to use bits 61 to 63 in MiSTer, so developers creating custom forks can use them. This can be used to provide custom inputs, for instance.
%% If JTFRAME_OSD60HZ is defined and the status word bit is low, MiSTer will disable the Scan FX options. This options should be used when the pixel clock is produced by a fractional divider, and thus it's very jittery. Some displays do good with this, some don't. This is less important for MiST because the PLL is less troublesome there. In MiSTer, all hell breaks loose in the HDMI subsystem for some game PLL settings.
Option visibility in MiSTer is controlled in jtframe_mister.sv using the status_menumask variable.
If JTFRAME_OSD_VOL is set, the dip_fxlevel inputs to the game module will vary according to the following table:
| OSD display | dip_fxlevel | Remarks |
|---|---|---|
| very low | 0 | |
| low | 1 | |
| high | 2 | Default |
| very high | 3 |
If JTFRAME_FLIP_RESET is defined a change in dip_flip will reset the game. Connect the game module flip signal directly to the DIP switch bit if this macro is used. Connecting it to the CPU controlled flip bit may create a lock during reset as the CPU flips the bit from the default value to that in the DIP settings.
To add game specific OSD strings, the recommended way is by adding a line to the .def file:
CORE_OSD=OD,Turbo,Off,On
Only one CORE_OSD can be defined, but it an contain multiple values separated by colon.
Screen rotation features require JTFRAME_VERTICAL to work. Remember to enable it first in the .def file. Screen rotation is done clockwise unless JTFRAME_ROTCCW is defined.
Most arcade games have a flip setting among the DIP switches. This is the preferred method to enable it. When that is not possible, using the JTFRAME_OSD_FLIP will add the option to the OSD. The option will appear outside the DIP Switches submenu in the OSD.
The current flip setting is kept in the dip_flip IO signal of the game module. This signal is an input or an output to the game module depending on whether JTFRAME_OSD_FLIP is set or unset:
| JTFRAME_OSD_FLIP | dip_flip type |
|---|---|
| set | input |
| unset | output |
Keep it simply defined as inout to avoid problems and assign a value to it when you don't use JTFRAME_OSD_FLIP.
JTFRAME_OSD_FLIP helps with the case when the original game did not have a DIP switch for flipping but it is still possible to design the graphics circuitry to have it. However, depending on how the original hardware operated, this may not be possible. An example of this is SEGA System 16. The sprite definition in that system is made in a way that makes very hard to flip the sprites without the game software intervention.
In cases where hardware flip at the base video signal is not possible, you can still flip the image directly in MiSTer by using the frame buffer. To enable this feature use the macro JTFRAME_ROTATE. This will add more options to the Rotate screen menu item in the OSD. These options will apply directly to MiSTer's frame buffer.
It is discouraged to use JTFRAME_ROTATE if the game already provides a flip setting through the DIP switches. Doing so can be confusing to the user. JTFRAME_OSD_FLIP is ignored if JTFRAME_ROTATE is defined.
The user port supports:
-DB15 joysticks using Villena's interface, support removed with JTFRAME_NO_DB15 -A simple UART, which can connect to the cheat engine (JTFRAME_CHEAT) or to the core JTFRAME_UART)
Depending on the three macros above are set or unset, the OSD menu will show different options in MiSTer.
Some JTFRAME features are configured via an ARC or MRA file. This is used to share a common RBF file among several games. The mod byte is introduced in the MRA file using this syntax:
<rom index="1"><part> 01 </part></rom>
And in the ARC file with
MOD=1
This is the meaning for each bit. Note that core mod is only 7 bits in MiST.
| Bit | Meaning | Default value |
|---|---|---|
| 0 | 1 = vertical screen | 1 |
| 1 | 1 = 4 way joystick | 0 |
| 2 | 1 = CCW rotation | Set by jtframe mra |
| 3 | 1 = unfiltered dial | Dial signals are sent raw to the core |
| 4 | 1 = dial reverse | Reverse dial direction |
The vertical screen bit is only read if JTFRAME was compiled with the JTFRAME_VERTICAL macro. This macro enables support for vertical games in the RBF. Then the same RBF can switch between horizontal and vertical games by using the MOD byte.