MegaST 1.1.4

Reset, cartridge and welcome screen fixes from tester reports.

Fixed

• Bombs after a reset (about 5 out of 10 resets, mostly STEroids, only a power cycle helped): a reset could hit the ST while it was reading TOS, and that read became a write: one word of the TOS in memory was overwritten until the next power on (TOS 2.06 reported "BAD ROM CRC", then bombs). TOS reads can no longer write. Reproduced and fixed in the simulator; tested on an R6 with STEroids and TOS 2.06: no bombs.
• A cartridge could not be removed: Space on the "Cartridge:" line now removes the cartridge, and the ST restarts without it.
• "config.vhd: No selected menu group item" when opening the menu: a settings file that does not match the menu stopped the core. Now a setting without a valid choice goes back to its default, and all other settings are kept.
• Coloured stripes behind the welcome screen: the welcome screen is now shown on black (also on VGA).
• The menu firmware wrote to a random memory address at start (framework bug); fixed.

Files

The menu is unchanged: the 104 byte atarist/stcfg and the 1536 byte atarist/stmount of 1.1 stay valid. Coming from 1.0 or older: copy the new atarist/stcfg from the zip.

File	Board	Status
MegaST-R6-v1.1.4.cor	MEGA65 R6	developer's board
MegaST-R3-v1.1.4.cor	MEGA65 R3/R3A (no SDRAM)	working on an R3A and an R3 (#2, #22); 512 KB ST RAM, no Viking, no STEroids

From 1.1.4 on there are no separate R4 and R5 core files. If you have one of these boards, please open an issue.

Known limitations: the real floppy drive is read only and DD only; the right button of an Atari mouse is a short click only and works about once every 10 seconds (#17); a tester saw some programs crash with 8 MB of ST RAM on an STe (4 MB works). The Mega STe mode starts at 8 MHz like a real Mega STE; set 16 MHz and the cache in XControl (as always before installing system software, back up your hard disk image first).

All changes: VERSIONS.md, manual: README.

MegaST is free and open source. If you enjoy it, you can support its development via Buy Me a Coffee or GitHub Sponsors.

MegaST 1.1.3

HDMI fix for the monochrome mode and a picture fix for STEroids.

Fixed

• The monochrome mode flickered on HDMI at 720p: small columns of the desktop pattern flickered at 720p (50 and 60 Hz), while 576p was stable. The scaler's frame buffer in the HyperRAM now uses 16 bits per pixel instead of 24 (the ST has at most 4096 colours, nothing is lost) and three buffers instead of one. Confirmed fixed by a tester.
• STEroids: the picture was cut off on the left. In the monochrome mode the first pixels of every line were missing (half of the first letter); the colour modes were shifted too. Also affected the Mega STe mode with the cache on. The picture is now in its place (verified in the simulator: pixel-identical to the STe mode).

Files

The menu is unchanged: the 104 byte atarist/stcfg and the 1536 byte atarist/stmount of 1.1 stay valid. Coming from 1.0 or older: copy the new atarist/stcfg from the zip.

File	Board	Status
MegaST-R6-v1.1.3.cor	MEGA65 R6	developer's board
MegaST-R5-v1.1.3.cor	MEGA65 R5	not tested yet, please report
MegaST-R4-v1.1.3.cor	MEGA65 R4	not tested yet, please report
MegaST-R3-v1.1.3.cor	MEGA65 R3/R3A (no SDRAM)	working on an R3A and an R3 (#2, #22); 512 KB ST RAM, no Viking, no STEroids

Known limitations: the real floppy drive is read only and DD only; the right button of an Atari mouse is a short click only and works about once every 10 seconds (#17); a tester saw some programs crash with 8 MB of ST RAM on an STe (4 MB works). The Mega STe mode starts at 8 MHz like a real Mega STE; set 16 MHz and the cache in XControl (as always before installing system software, back up your hard disk image first).

All changes: VERSIONS.md, manual: README.

MegaST is free and open source. If you enjoy it, you can support its development via Buy Me a Coffee or GitHub Sponsors.

Test build: mono HDMI flicker at 720p (1.1.3-test2, R6)

Test build, not a release. MEGA65 R6 only.

This build tests a fix for the flickering monochrome picture on HDMI at 720p (50 and 60 Hz). 576p was not affected.

What changed: the scaler frame buffer in HyperRAM now uses 16 bits per pixel instead of 24. That halves the memory traffic, so the scaler no longer reads lines late. Triple buffering is also on (from 1.1.3-test1).

Install: flash MegaST-1.1.3-test2-R6.cor to a core slot. Keep your existing /atarist folder. stcfg and tos.img are unchanged from v1.1.2.

Please report:

• Monochrome (71 Hz) at HDMI 720p 50 Hz and 720p 60 Hz: is the flicker gone?
• Do the colour modes still look right? 16 bpp can show slightly coarser colour gradients.

For normal use, stay on v1.1.2.

MegaST v1.1.2: no reset delay with the real floppy drive

Bug fix for the real floppy drive: with "Real floppy drive as A:" switched on, every reset took 5 to 10 seconds longer.

Fixed

• Drive B: is not connected while the real drive is on. At every reset TOS checks whether drive B: is there (TOS 2.06 sends it 7 commands that move the head to track 0). On a missing drive the floppy controller stepped for up to 1.5 seconds per command looking for track 0, and TOS waited for each one. The controller now answers these commands for drive B: at once, with the result of a missing drive. TOS still sees no drive B: (as before), just without the wait.
• With no disk in drive A:, TOS still waits a moment for drive A:, as on a real ST.
• Tested on an R6 and in the simulator (TOS 1.04, TOS 2.06 and EmuTOS).

Files

The menu is unchanged: the 104 byte atarist/stcfg and the 1536 byte atarist/stmount of 1.1 stay valid. Coming from 1.0 or older: copy the new atarist/stcfg from the zip.

File	Board	Status
MegaST-R6-v1.1.2.cor	MEGA65 R6	developer's board, reset fix tested
MegaST-R5-v1.1.2.cor	MEGA65 R5	not tested yet, please report
MegaST-R4-v1.1.2.cor	MEGA65 R4	not tested yet, please report
MegaST-R3-v1.1.2.cor	MEGA65 R3/R3A (no SDRAM)	working on an R3A and an R3 (#2, #22); 512 KB ST RAM, no Viking, no STEroids

Known limitations: the real floppy drive is read only and DD only; the right button of an Atari mouse is a short click only and works about once every 10 seconds (#17); a tester saw some programs crash with 8 MB of ST RAM on an STe (4 MB works). The Mega STe mode starts at 8 MHz like a real Mega STE; set 16 MHz and the cache in XControl.

All changes: VERSIONS.md, manual: README.

MegaST is free and open source. If you enjoy it, you can support its development via Buy Me a Coffee or GitHub Sponsors.

MegaST v1.1.1: real floppy drive fix for EmuTOS

Bug fix for the real floppy drive with EmuTOS (#24): with "Real floppy drive as A:" switched on, the EmuTOS desktop showed no drive icons.

Fixed

• EmuTOS checks at start-up whether a floppy drive is connected: it stops the floppy controller ("force interrupt") and moves the head to track 0. The controller (WF1772IP) had a bug: a "force interrupt" while it was idle restarted its previous command, which then waited for the disk to spin up, and it ignored the next command. So EmuTOS saw no drive A:. Atari TOS showed the icons anyway, because its desktop always shows A: and B:.
• Drive B: is still not available while the real drive is on (as in 1.1).
• Tested on an R6: EmuTOS 1.4 shows DISK A on the desktop. In the simulator TOS 2.06 boots as before.

Files

The menu is unchanged: the 104 byte atarist/stcfg and the 1536 byte atarist/stmount of 1.1 stay valid. Coming from 1.0 or older: copy the new atarist/stcfg from the zip.

File	Board	Status
MegaST-R6-v1.1.1.cor	MEGA65 R6	developer's board, EmuTOS floppy fix tested
MegaST-R5-v1.1.1.cor	MEGA65 R5	not tested yet, please report
MegaST-R4-v1.1.1.cor	MEGA65 R4	not tested yet, please report
MegaST-R3-v1.1.1.cor	MEGA65 R3/R3A (no SDRAM)	working on an R3A and an R3 (#2, #22); 512 KB ST RAM, no Viking, no STEroids

Known limitations: the real floppy drive is read only and DD only; the right button of an Atari mouse is a short click only and works about once every 10 seconds (#17); a tester saw some programs crash with 8 MB of ST RAM on an STe (4 MB works).

All changes: VERSIONS.md, manual: README.

MegaST is free and open source. If you enjoy it, you can support its development via Buy Me a Coffee or GitHub Sponsors.

MegaST v1.1: floppy disk support (internal drive, read only)

Floppy disk support: the MEGA65's internal 3.5" drive works as the ST's drive A: (read only, #15). Original Atari ST disks, including copy protected games, are read as on a real ST. Please report which disks work and which don't in #15.

New

• "Real floppy drive as A:" in "System settings" (off by default), then "Reset Atari ST": drive A: is the disk in the MEGA65's drive. The core has a complete WD1772 floppy controller (WF1772IP by Wolfgang Förster), so copy protections and formats with 10 sectors and 82 tracks work. Drive B: and the floppy images are not used while it is on.
• "Floppy read assist" in "System settings" (on by default): the MEGA65 drive's speed varies by up to 8 % within each turn of the disk, and the WD1772 then misreads a sector now and then; some loaders keep the wrong bytes and hang. A data separator in front of the controller re-times the drive's pulses, and a sector that fails its checksum is read again (up to 15 more turns) before the ST gets it.
• Tested on an R6 with an original-format Jim Power disk (82 tracks, 10 sectors): boots and loads the game with no read errors.

Limits: read only (the core never writes to the disk; games that save to the disk get an error), DD disks only. A worn or badly written disk can still fail even if it reads in a PC drive: an older copy of the test disk had a weak spot that needed 26 turns. The R3/R3A, R4 and R5 cores are built from the same source but not tested with the drive yet.

Files

The menu has two new lines: copy the new 104 byte atarist/stcfg from the zip to the SD card. The 102 byte file of 1.0 is reported as corrupt and the settings are not saved. The 1536 byte atarist/stmount stays valid.

File	Board	Status
MegaST-R6-v1.1.cor	MEGA65 R6	developer's board, floppy drive tested
MegaST-R5-v1.1.cor	MEGA65 R5	not tested yet, please report
MegaST-R4-v1.1.cor	MEGA65 R4	not tested yet, please report
MegaST-R3-v1.1.cor	MEGA65 R3/R3A (no SDRAM)	1.0 working on an R3A (#2), floppy drive not tested; 512 KB ST RAM, no Viking, no STEroids

Known limitations: the right button of an Atari mouse is a short click only and works about once every 10 seconds (#17); a tester saw some programs crash with 8 MB of ST RAM on an STe (4 MB works).

All changes: VERSIONS.md, manual: README.

MegaST is free and open source. If you enjoy it, you can support its development via Buy Me a Coffee or GitHub Sponsors.

MegaST v1.0: first stable version, HDMI centred, Atari mouse right click fix

The first stable version. Since the first beta (0.4.6) the floppy and hard disk images, the keyboard, the mice, the joysticks and the settings have been tested by the developer and by testers on R6 and R3A boards. Please keep reporting what works and what doesn't in the issues.

New

• HDMI picture centred: in 576p (4:3 and 5:4), 720x480 and 640x480 the right side of the picture was cut off and the picture looked shifted to the right. The scaler now shrinks the ST line to fit, so both borders are equal.
• "Remember floppies" and "Remember TOS/cartridge" in "System settings" (both on by default): switch one off to start without the last floppies or without the last TOS/cartridge (then tos.img is used). Hard disks are always remembered.
• MEGA + F1..F9 gives Shift+F1..F10 (F11..F20 in GFA-Basic and STOS, #18): MEGA + F1/F3/F5/F7/F9 for Shift+F1/F3/F5/F7/F9, MEGA + Shift + F1..F9 for Shift+F2..F10.

Fixed

• Right button of the Atari mouse (#17): after a right click GEM saw the button held for 10 seconds and ignored left clicks meanwhile. Measured on an R6: the Atari mouse only grounds pin 9, and without the ST's pull-up the line takes 10-13 seconds to float back up after a release, so the core can not see the release. With Mouse type = Atari a right click now counts as a short click (200 ms): right-click menus work, holding the right button does not, and a second right click only counts about 10 seconds later.
• mouSTer: with firmware 3.23.5313 or newer the right button works in Amiga mode with activepotlines=true, or in 1351 mode (#17, thanks @hkramer70). The INI settings are in the README.

Files

The menu has three new lines: copy the new 102 byte atarist/stcfg from the zip to the SD card. The old 99 byte file is reported as corrupt and the settings are not saved. The 1536 byte atarist/stmount of 0.4.12 to 0.4.14 stays valid.

File	Board	Status
MegaST-R6-v1.0.cor	MEGA65 R6	developer's board
MegaST-R5-v1.0.cor	MEGA65 R5	not tested yet, please report
MegaST-R4-v1.0.cor	MEGA65 R4	not tested yet, please report
MegaST-R3-v1.0.cor	MEGA65 R3/R3A (no SDRAM)	working on an R3A (#2); 512 KB ST RAM, no Viking, no STEroids

Known limitations: the right button of an Atari mouse is a short click only and works about once every 10 seconds (#17); a tester saw some programs crash with 8 MB of ST RAM on an STe (4 MB works).

All changes: VERSIONS.md, manual: README.

MegaST is free and open source. If you enjoy it, you can support its development via GitHub Sponsors.

MegaST v0.4.14 beta: restored hard disks work, mouSTer right button fix

Pre-release for testing. Please report what works and what doesn't in the issues (core version, board, TOS, machine settings, disk image).

Fixed

• Hard disk not seen by TOS after power-on (#11, #12): since 0.4.12 the core restores the remembered images at power-on and after a long press of the reset button, but it ejected them again right away inside the core, while the menu still listed them. Images mounted in the menu while the ST was running were not affected. "Reset Atari ST" in the menu ejected the images, too. Please test: mount your hard disk image, switch off and on, and check that TOS shows its drives.
• Right mouse button stuck with a mouSTer (#17): pin 9 of the mouse port has no pull-up on the MEGA65, so a mouSTer that leaves it open (or a joystick in the mouse port) looked like a held right button, and GEM ignored clicks on window controls. The core now ignores the right button until it has seen pin 9 released. An Atari or Amiga mouse keeps its right button; a mouSTer in Atari mode has none.

Files

Unchanged menu: the 99 byte atarist/stcfg and the 1536 byte atarist/stmount of 0.4.12 and 0.4.13 stay valid (stmount lets the core remember the mounted images, #13). Coming from 0.4.7 or older, copy the new atarist/stcfg from the zip, otherwise the settings are not saved. Hard disk images written with 0.4.10 or older may be damaged (#11): restore them from a backup.

File	Board	Status
MegaST-R6-v0.4.14.cor	MEGA65 R6	developer's board
MegaST-R5-v0.4.14.cor	MEGA65 R5	not tested yet, please report
MegaST-R4-v0.4.14.cor	MEGA65 R4	not tested yet, please report
MegaST-R3-v0.4.14.cor	MEGA65 R3/R3A (no SDRAM)	working on an R3A (#2); 512 KB ST RAM, no Viking, no STEroids

All changes: VERSIONS.md, manual: README.

MegaST is free and open source. If you enjoy it, you can support its development via GitHub Sponsors.

MegaST v0.4.13 beta: function key and right mouse button fixes (restored hard disk not seen)

Pre-release for testing. Please report what works and what doesn't in the issues (core version, board, TOS, machine settings, disk image).

Fixed

• Function keys (#16): F6, F8 and F10 (Shift+F5/F7/F9 on the MEGA65) sometimes arrived as Shift+F6/F8/F10, so programs like GFA Basic reacted wrongly. The ST's keyboard processor could still see Shift in the moment the F key appeared; the F key now follows 20 ms later.
• Right mouse button (#17): the right button of an Atari mouse (or a mouSTer adapter) did nothing. It now works like the right button of the Amiga mouse. Please test with your mouse, and also check that a joystick in the mouse port does not act as a held right button.
• More timing margin for the HyperRAM clock on all boards.
• README: new guide Using disk images (floppy and hard disk step by step, FAQ). To unmount (eject) a drive, select its line in the menu and press Space.

Known problem

Some users report that a hard disk image is mounted but not seen by TOS since 0.4.12 (#11, #12), also after the core restored it at power-on. The same image boots in the simulator, so it is being investigated on real hardware. If a remembered image is not seen after power-on (#11): unmount it, reset and mount it again.

Files

Unchanged menu: the 99 byte atarist/stcfg and the 1536 byte atarist/stmount of 0.4.12 stay valid (stmount lets the core remember the mounted images, #13). Coming from 0.4.7 or older, copy the new atarist/stcfg from the zip, otherwise the settings are not saved. Hard disk images written with 0.4.10 or older may be damaged (#11): restore them from a backup.

File	Board	Status
MegaST-R6-v0.4.13.cor	MEGA65 R6	developer's board
MegaST-R5-v0.4.13.cor	MEGA65 R5	not tested yet, please report
MegaST-R4-v0.4.13.cor	MEGA65 R4	not tested yet, please report
MegaST-R3-v0.4.13.cor	MEGA65 R3/R3A (no SDRAM)	working on an R3A (#2); 512 KB ST RAM, no Viking, no STEroids

All changes: VERSIONS.md, manual: README.

MegaST is free and open source. If you enjoy it, you can support its development via GitHub Sponsors.

MegaST v0.4.12 beta: remembers mounted disks (restored hard disk not seen, fixed in 0.4.14)

Pre-release for testing. Please report what works and what doesn't in the issues (core version, board, TOS, machine settings, disk image).

New: the core remembers your disks (#13)

• The mounted floppy and hard disk images and the TOS and cartridge chosen in the menu are loaded again at the next start, before the ST boots, so a hard disk is found and the right TOS starts.
• This needs the new file atarist/stmount from the zip (1536 bytes) on the SD card. Without it, the core behaves as before.
• Unmounting a drive in the menu forgets it. An image that is no longer on the SD card is skipped.
• A long press of the reset button restarts the core like switching off and on, so the remembered images come back. Unmount them in the menu if you want empty drives.
• Tested in the QNICE emulator, not yet on real hardware: please report whether it works (mount disks, switch off and on, check that they are back).

The menu is unchanged: the 99 byte atarist/stcfg of 0.4.8 to 0.4.11 stays valid. Coming from 0.4.7 or older, copy the new atarist/stcfg (99 bytes) from the zip, otherwise the settings are not saved.

⚠️ Coming from 0.4.10 or older

Hard disk writes were broken up to 0.4.10 and fixed in 0.4.11 (#11). Hard disk images that were written to with 0.4.10 or older may be damaged: restore them from a backup or check them.

Core files in the zip

File	Board	Status
MegaST-R6-v0.4.12.cor	MEGA65 R6	developer's board
MegaST-R5-v0.4.12.cor	MEGA65 R5	not tested yet, please report
MegaST-R4-v0.4.12.cor	MEGA65 R4	not tested yet, please report
MegaST-R3-v0.4.12.cor	MEGA65 R3/R3A (no SDRAM)	working on an R3A (#2); 512 KB ST RAM, no Viking, no STEroids

All changes: VERSIONS.md, manual: README.

MegaST is free and open source. If you enjoy it, you can support its development via GitHub Sponsors.