Questions about the BLL loader

[timothyscarlson]

Hey all,

 

I'm working on a ROM emulator for the Lynx based on a PIC18F4550. I have a few questions about the BLL loader found in the BLL020409.ZIP archive, the loader.lyx file, dated 01/02/1997.

 

For background, I am able to load and run raw cart images (without an emulator header), LYNX emulator images, and BS93 images. I also have Karri's fast boot loader working. Images I can run are Karri's PONG, Pong1K, Ghosts And Ghouls demo, Megaman demo, T-Tris, Centipede, and Cartshow. I am limited to small images - just under 32K - which is a limitation of the PIC (for now).

 

So - here's the questions:

 

1) Is the loader.lyx file a raw cart file? Should you be able to just burn it into a ROM and run?

2) What size ROM does it expect to reside in?

 

All I get when I attempt to run the BLL loader is - it reads the first block of 52 - then it reads the next block - then it reboots and starts again. I see the 'INSERT GAME' message barely flashing on the screen.

 

I thought that since it has a .LYX (instead of .LNX) extension, it would just be a raw ROM image. It doesn't seem to work that way, however.

 

BTW: I am using a LYNX I for my development.

 

Thanks in advance!

[sage]

what are you aiming for?

 

That "loader" question has been discussed several times before, check the forum.

 

I hope you are not misunderstanding the serial loader ROM by the troyan-hijacked bootloader, are you?

Edited February 14, 2013 by sage

[sage]

Please check with an hexeditor what is written at the end of the loader:

Is it "Loader2.5 © 95" or "Loader2.6 © 98"?

[sage]

I checked even so i am not sure if I have the same version.

 

a) The image contains the bll serial loader

b) it is not executeable, either because

b1) its broken

b2) requires a strange ROM layout

b3) has checksumming enabled (might req. $FF for the rest of the ROM)

 

Checking against a valid and working ROM dump, I conclude that at least my version is broken.

If your image has a $23 at position $50, its broken too. Its very unlikely that you have a valid encrypted rom with the same content shifted by one byte :-)

You can easily check by comparing the first 512 bytes of the ROM against the first 512 bytes of gauntlet. they should be identical.

 

 

Add: all hex $1a are stripped from my loader.lyx ... seems some kind of editor dint like it...

Edited February 14, 2013 by sage

[timothyscarlson]

Yup - corrupted loader in the archive. All hex $1A stripped.

 

I guess my goal was to get everything that would fit in the PIC memory to work. Since I can load images from the PIC already, I really don't need the loader - unless my images grow beyond 32K-$140.

 

So now that I know I'm not crazy and the image is actually broken, I'll move on. I'll also search the forum for the loader info you mentioned.

 

Thanks!

[sage]

I guess my goal was to get everything that would fit in the PIC memory to work. Since I can load images from the PIC already, I really don't need the loader - unless my images grow beyond 32K-$140.

 

where the serial will not help you much as it is limited to memory size.

[timothyscarlson]

Well, the BLL loader was my first line of attack when I started this project. But, as I became more familiar with the Lynx and Lynx images and putting images in the PIC program memory, the BLL loader priority dropped. It's the last image on my list of images I wanted to have working on my setup, so I could have a bit of closure before I continue on.

 

Eventually I want to have either a USB interface so I can connect a thumbdrive with images, or an SD Card interface - again, with images. Or something else, if I find some hardware that's more compelling than what I have available now. So the current limit of (slightly less than) 32K will eventually disappear.

 

This all started because I have a Lynx I and a Lynx II, but no game carts. Unfortunately, those all went away after my previous life imploded. I was going through boxes of leftover stuff and found the Lynx systems and decided I either needed to figure out a way to load games on the systems or scavenge the systems for parts - and I didn't want to destroy them. This is just a retirement project, something to keep me busy and interested and learning.

[timothyscarlson]

Back to the BLL Loader - can someone point me to a link that has a good copy of the BLL loader? Both the old (bll991112.zip) and new (bll020409.zip) archives I have found on the net are bad in the same way (stripped of hex $1A characters).

 

Edited: I would like to put the BLL loader as working on my list, even though it's not really necessary for my development. I do have a BLL cable I gen'ed up using a USB FTDI part, and it would be nice to see if it works with the loader.

 

Edited again: Nevermind - searching the forums, I found Karri's TESTFLASH.LYX and SEND_OBJ.EXE files. Going to test it now.

Edited February 16, 2013 by timothyscarlson

[sage]

The sourec code is within the BLL package, you just have to include it in a small programm.

I think its caled InstallUpLoader or so.

you will miss the menu for switching the speed.

[+karri]

For the PC I use a program Mttty.exe. It can send bll files from a pc to lynx.

mttty.zip

[timothyscarlson]

Yes! Thanks, Karri - that works!

 

Only at 9600 baud, tho. I will have to see what I need to do to get the FTDI USB-Serial device to run the other Lynx baud rates.

 

BTW: you created the TESTFLASH.LYX image that has the BLL-Loader incorporated. Very nice, thanks! I was playing around with some of the flash/eeprom tests, and the address test fails (on my hardware) with the error message "problems". Heh. Since part of my project is wiring up the Lynx ROMAX lines to the PIC18F4550, I would be interested in having some expanded information as to what the "problems" are.

 

Is the source code / build tree for TESTFLASH available anywhere?

[+karri]

I can dig up the source code. It was compiled on some hacked version of the old C-compiler called newcc65

 

The Mttty.exe works with FTDI chips too. It has support for 62500 and 31250 bauds also. But to get them to work you need some cart that can set up the baudrates correctly on the Lynx side.

 

The USB-Serial ports show up as higher COM ports like COM5:, COM8: and so on.

 

The MegaPak I has support for higher rates.

 

The testflash uses some very special code for writing to Intel StrataFlash and serial EEPROMs.

[+karri]

The testflash code is actually written mainly by Matthias Domin,

 

I just added the tests to his hex display code.

testflash.zip

[timothyscarlson]

Ah, okay - so the TESTFLASH image has the baud rate on the Lynx fixed at 9600. So if I either find another loader image like MegaPak I, or modify TESTFLASH for a higher baud rate, the FTDI device will work okay. Cool.

 

My FTDI device is on COM7:, which works just fine. At 9600 baud. We'll see about the higher baud rates later.

 

I'm not too concerned about the flash/serial eeprom writing (for now) - I just want to do a bit more comprehensive diagnostic - basic stuff like checking the address/data/control lines to the ROMs, a RAM test, interrupt tests, screen test, button tests, MIKEY/SUZY tests, etc. My career background was in new silicon validation/writing validation & diagnostic code. I find the best way to understand the hardware is to write the diagnostics for it. So that would be a good first Lynx program for me to tackle. It would also help me validate the emulator hardware I am developing.

 

Source code? Yes, please Thanks in advance.

 

And I'll pass back anything good I may come up with.

[timothyscarlson]

The testflash code is actually written mainly by Matthias Domin,

 

I just added the tests to his hex display code.

 

Thanks! It's late here now, so I'll peruse this tomorrow.