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Lynx Multi Cart


SainT

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Yes got to stop with it, i got to wait for ansure, HOWEVER instead of recieving an email or post in my message post,depends per person how to ansure, i got to go trough that whole thread to find the ansure in between those threads,that's like finding some litle rocks in sand.

This whole site DIT confuses me but i slowly start to know all ins & outs of it, well i guess i got way too much spare time to boring the crap outa me.

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@johannesmutlu.. Did you bump every single lynx thread??

 

It's like you pushed every button on the elevator in the Burj Khalifa ?

Yes i dit,am sorry, because i was sooooo confused about the ins & outs of this site, thinking that my posts weren't viewed on this site ,so i desperately posted the same thing over and over again,untill i realize that they were viewed on this site but by the time i realised this, it was already to late and i cannot reject my massages either whatever i tryed aaarrrgggg???

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Yes i dit,am sorry, because i was sooooo confused about the ins & outs of this site, thinking that my posts weren't viewed on this site ,so i desperately posted the same thing over and over again,untill i realize that they were viewed on this site but by the time i realised this, it was already to late and i cannot reject my massages either whatever i tryed aaarrrgggg

What the hell kind of site wouldn't see or respond to posts? Just curious.

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@johannesmutlu: please stop. When the OP has something to announce he will let everyone know. :roll:

Sorry there was a HUGE miscommunication, turns out that i somehow accidentally blocked atariage, so i couldn't recieve any email, untill i discovered the issued and deblocked the site, so now i can recieve & response those emails from those ones whose got to tell me something.

Again am sorry and am up to date now.

Fixed.

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Ok, found some time to have a play. I have it working now -- got a directory browser written which will then launch LNX ROM images.

 

There's a couple of weird things still to iron out -- writing to the cart seems a bit flaky. I've managed to get it working with a massive delay loop, just need to figure out what the actual problem is. Seems to be some noise on the data lines, perhaps caused by polling the AUDIN pin? Not sure.

 

The other odd thing is that some games have no audio when launched from the file menu, but are just fine when launched directly. I assume I'm going to have to try and reset all the hardware to a power-on state before jumping to the boot ROM...

Hi, i know you,re buzzy with everything,but please i need to know 1 VERY IMPORTANT thing about your prototype sd flashcard.

I suppose i do NOT have to moddifie my lynx2 to make it work with multiple roms on it? Or does it require some moddifications to the lynx2???

I will be so releaved to recieve a ansure from you.

.

Thanks alot.

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Hi, i know you,re buzzy with everything,but please i need to know 1 VERY IMPORTANT thing about your prototype sd flashcard.

I suppose i do NOT have to moddifie my lynx2 to make it work with multiple roms on it? Or does it require some moddifications to the lynx2???

I will be so releaved to recieve a ansure from you.

.

Thanks alot.

Pretty sure the final release will be plug and play like every flash cart for every system ever. Just select the rom title from a boot menu to excecute said game. You only get into modding in the CD era since most CD systems required mod chips to run burned CDRs...

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Yep, indeed, it's just a cartridge. Plug and play...

 

Oh, and it looks like it should fit in the Lynx 1, no problem. Haven't tested it running yet though as I'm just using a plastic shim in the Lynx 2 to get the cart the right width and access to the cart connector on the Lynx 1 is a bit tricky -- need to attach it properly. :)

 

Many thanks goes to LX.NET for the Lynx 1 for testing. :thumbsup:

Edited by SainT
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Sorry there was a HUGE miscommunication, turns out that i somehow accidentally blocked atariage, so i couldn't recieve any email, untill i discovered the issued and deblocked the site, so now i can recieve & response those emails from those ones whose got to tell me something.

Again am sorry and am up to date now.

Fixed.

 

Oh, that's great! ;-)

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  • 4 weeks later...

Does anyone know if there are any issues with writing to CART1? I'm getting odd corruption when writing to CART1 more than a few bytes at a time unless I put a large delay either side of the write, then it's ok. Really odd.

 

I know the external cart bus is multiplexed to read the joypad, but I'm not reading the pad during the writes and even so, the write operation should be atomic. At the moment this is the last thing that needs fixing.

 

Any thoughts appreciated...

 

One thing I will say though -- it's consistently wrong! I can repeat it as many times as I like and it gets the same (wrong) result.

Edited by SainT
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Weirdly it also only seems to be certain bits which get zero'd. It's like there's something on the bus pulling certain bits low -- it happens in both the high and low nibble. If this sounds familiar to anyone please shout... :)

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I found this on read and writes from the developer docs (not sure if this helps):-

 

ROM Cart Data Read

In order to prevent a reduction of battery life when using the ROM Cart, we only enable the ROM itself when we wish to read a data byte. We do it in such a manner as to guarantee that no RAM access can occur simultaneously with a ROM access. This is achieved by driving one of the chip enable lines from SUZY. The trailing edge of this chip enable signal also advances the address counter by 1. Only one address is available to the Cart and the activation of either chip enable signal will increment the address.

The 8 tri-state data bits of the ROM are tied to 8 of the switch reading lines on SUZY. The switches are isolated from the ROM by resistors. When a read request comes from MIKEY, Suzy will hold off MIKEYs DTACK, enable the ROM (which overdrives any pressed switches), wait 437.5 ns (for ROM access time), and disable the ROM. Towards the end of the wait, SUZY passed the data from the ROM to Mikey and released the DTACK. The actual access time available at the pins of the Cart is 392ns. The CPU cycle that performed the actual read uses 15 ticks of the clock.

 

ROM Cart Data Write
The ROM Cart can also be written to. The addressing scheme is the same as for reads. The strobe is also self timed. The length of the strobe is 562.5 ns, the data is stable for 125 ns prior to the strobe and for 62.5 ns after the strobe. This is a blind write from the CPU and must not be interrupted by another access to Suzy until it is finished. The CPU must not access Suzy for 12 ticks after the completion of the blind write cycle.

Edited by GadgetUK
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Right, sorted it. I was trying to use CART1 for write and read, and hadn't noticed I was always driving the bus when CART0 or CART1 strobes were active, which was corrupting the data writes.

 

So I've switched this to now use CART1 for write and CART0 for read and it's working perfectly now.

 

The last odd thing is some games have no sound, but do when booted without the menu -- there's something being initialised in the menu code which isn't being reset correctly by all games. So I just need to sort that out, and could do with speeding up the firmware a bit (it's quite slow to program the cart image) and we're finished! :D

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