Zikzak - crummiest 8bit console/computer ever .. but I'm making it!

[panik]

The only real problem is the damned LQFP100 and up. LQFP64 is bad enough to solder.. 100pin is a bit of a nightmare   On the one hand, theres a place near me that actually sells QFP64->DIP64 adaptors, which is what I use for prototyping.. but they're $10-$15 a piece (currently $15, ouch!), though a bit cheaper if you place some tricks. Still, I'd have to make my own.. really, shoudl be able to get them for $5 a piece if I make them myself, or less. Anyway. Very few reputable places make QFP100 and up adaptors.. I've got some from Thailand, but they're these big huuge affairs, and not the best.

These 100 pin LQFP adaptors are $1,50 each: https://www.futurlec.com/SMD_Adapters.shtml (near the bottom of the page), but it takes at least 4 weeks before you have them. Maybe you meant these with "big and not the best".

The thing with adaptors though, you still have to solder not only the chip on the adaptor, but also the pins (and sockets). Cool for prototyping, but an adaptor doesn't save you from soldering a 100 pin chip somewhere. Might as well have it directly on the PCB.

 

[skeezix]

Futurelec is a funny one; I generally avoid them. Theres a lot of bad blood around the net.. some people had really poor service (got nothing, at all, ripped off), where a lot of people have just had slow; myself, I ordered once and it took something like 9 weeks to arrive, but it did. When it did arrive (abot 40 ICs of various kinds).. thery were mostly right, but some were wrong.. they swapped package types, so I got some surface mount of various kinds, inmstead of DIP, but same part number. Cheap as hell, but you get what you pay for in service

Mind you, I also ordered a pile of sockets from them .. around me, a tin socket is about 10c/pin (a 40pin socket is $4).. just brutal. From futurelec a year ago, I got them for 15c each or something, some as low as 5c. They're cheap for sure, and melt if you look at them funny, but they work. You just can't argue with those prices sometimes.

So Futurelec is on the list of possible stores, but for me, its way down at the bottom

--> those square SMT adaptors aren't really useful imho; they do get you a DIP board, but then its still not breadboardable, so you have to in turn make a perfboard to map it out for BBing sake. Bit of a drag.. but I get it, with 100+ pins, its hard to justify a shark-fin thats 50 pins or more wide (I've done it.)

.. The reason I bring up adaptors is specifically for this:

- Assuming I make a few kits..

.... most people are terrified of surface mount soldering for any high numebr of pins (say 48+, certainly 64+).

... I have some equipment that makes it a bit easier for me (solder paste, rework station, and a magnifier microscope (Andonstar ftw!))

... it shifts the error to me, not downstream kit buyer.

--> so I could sell a already solder-to-adaptor set of cpu options for those who are afraid to risk soldering the SMT ICs themselves

If its just me, I'd just put the SMT parts on the board and call it a day.

Its that question.

- build for me?

- build for you guys?

- build for public? (newbies?)

- and design for production (based on limits of selected boardhouse, etc)

Really, I should just build it for me, rev1, and see if anyone wants it from there, but I rather like to keep the options for everyone else in mind

jeff

edit: You're right though, adaptors for QFP64 variants, for shipping out are cheap. (QQFP and LQFP tend to differ.. even two different QDFP adaptors you have to be careful; theres multiple pitches and pin widths called TQFP or LQFP; I've got some adaptors that handle both .. one pitch one side, flip it over for the other pitch, that sort of thing. Crazy, but you have to be careful.)

... let me check the specs on the ez80 lqfp100 .. if that tqfp adaptor fits, it coudl be an option if I can solder it reasonably successfully myself. Thanks for that idea..

edit the secundus:

okay, its hard to see in the ez80 lqgp100 specs; it is clear the pin spacing ("BSD" pitch) is 0.5mm (same as TQFP100 usually); the pin widths isn't on the datasheet.. theres a couple arrows there, but no definition, doh Still, perhaps the 0.5mm pitch is all you need.

I've got a few of those TQFP adaptors already, so maybe I'll try it out.. if its easy enough with my rework station, it could be a valid option.. give me $10/processor or something, and you can plug in whichever module you want or something.

 

[slaeshjag]

Wow, I had never heard about such problems from futurlec. I've bought stuff from them half a dozen times and always gotten what I've ordered

 

[skeezix]

Really, I should put together a board layout for a couple adaptors; can't be that hard to make a LQFP100 adaptor and then just have one of those boardhouses knock it out, see if it works. I keep thining I'd like to make that sort of thing, for all the adaptors I need for zikzak, and knock it out.. 1 board is all the adaptors needed.
 Then head over to my dads palce where he has a bandsaw and zip through them quick to separate (sure you can use a utility knife, but thats no _fun_

jeff

 

[skeezix]

Wow, I had never heard about such problems from futurlec. I've bought stuff from them half a dozen times and always gotten what I've ordered

Seems hit or miss; on my first order I was pretty worried I'd just lost the money, after the stuff you read on various forums or BBB, etc. At the same time, they've been around a lot of years and a lot of people do like them - as long as you have time to wait - so that seems legit; slow, but so cheap, its worth it sometimes.

But like I said, I've seen weird part swaps and dubious quality; still, if you're getting something for 10c and its a few bucks elsewhere, what can you say? even if half the stuff is junk...

--> FWIW, I keep a couple of large anti-static bags to hold my parts inventory; I have a separate bag just for futurelec stuff, since its questionable; never had a problem anywhere else.

honestly, some peopel seem to have bad lucl; order caps, and you open them up and find theyu're empty or full of another crappier cap, etc; weird stuff. I've never really had a problem .. maybe been ripped off on ebay once or twice; out of a hundred or two orders over the years, always had good luck for the most part...

jeff

"Your account" link in one page goes to Contact Us; in another page, it goes to Error.html

I played an order for a couple thigns, for fun, see how it turns out ... they didnm't ask for CC, so presumably they kept in on file (?), but since My Account is borked.. no way to know

 

[panik]

Futurlec: Yes, you get what you pay for. I've had an order take over 3 months. Also, their packaging is horrible for SMT chips (cellotaped to white foam, wrapped in plastic that's stapled together). Don't order from them if you're in a hurry. They're alright for 'hardware' though, like buttons, connectors, protoboard etcetera (I've had squashed USB connectors though. Really, totally flat as if a sea container fell on it). But http://www.taydaelectronics.com/ is even better for that.

The square adaptor boards are indeed unsuitable to use for breadboarding. But I generally don't use breadboards. I tend to want to save my projects, so most of the time I solder everything to a $1,- protoboard. It's more expensive (and takes more time), but just a little bit. Still less than a couple of beers in a bar, and more fun.

I can imagine you selling kits (eventually) with only the hardest to solder parts soldered to it; the 64+ pins chips. The rest is pretty easy to solder by the end user. SMT caps and resistors are even easier (and faster) to solder than their DIP counterparts. I was surprised when I found that out

 

[skeezix]

Soldering is 'scary' to some folks; once you get good at it, and learn some tricks, its like magic When I first found out about drag soldering for SMT I was 'nooo way, it can't!' and then poof, it works pretty well; then you see a heat gun in action with solder passte and your jaw drops. Hell, I even tried soldering on stovetop as I've got a 20 year old beater stove right beside my office .. put a hot pan on it, put pcb on that, warm it up slow and then crank it up and poof, you can solder SMT like that

I do like breadboarding.. its _fun_ .. just so easy, slap a chip down, jack in the wires and see what happens. Its risky though... stray capacitance etc, but for a quick expertiment it can't be beat. For zikzak I've done a lot of little tests .. as you can see over this thread, I've tried a half dozen microcontrollers, against various sound chips, with various VGA hookups .. I don't want to have 30 or 40 perfboards of aborted things around; I don't find re-0using perfboards works too well .. theyr'e covered in solder and gubk, or the pads are 'unreliable' (partially lifted in some spots); with how little free time I get, I want to reduce the surface area for problems. I did pick up one of those ebayt '50 shitty little paper perfboards for $10' sort of things, which are handy.. but not big enough or reliable enough for a lot of my experiments.

So in the end.. I've got my Enormous breadboard (the 10 breadboards together one), and a high quality 3 breadboard one, that I use for a lot of stuff.

The perfboards is for stuff I'd like to keep (my prototype zikburners, that sort of thing.)

Also, perfboards look awesome; its important to have these little permanent boards lieing around for the kids to -what the hell is that?- at

The AY-3-89xx sound chips are awesome to ahev ltitle boards lieing around making weird noises

Think I might buy an Eagle license; the free edition limits really annoy me; you can torrent down a full copy of course, of Altium and all those other guys, but I like to be on the legal side of things; Eagle is $150, a bit steep for hobbyist, but that at least gets ytou 6"x4" boards; even thats too small for the money imho, but what can you do.

(Getting a small $bonus at work this year, so.. Eagle? )

jeff

Tempted to order a couple ez80s.. maybe can get some samples from Zilog, but how to wire them up. I'd love to get some Xilinx Spartan FPGA samples or units to play with, but I've ruled them out of zikzak for now .. I'd love an fpga video card, but I think thats for Rec5 sort of thing, not anytime soon.

Why do we have to work for a living? It gets in the way

 

[WizardStan]

I wonder if my burner can handle eZ80 chips. It's looking way better than the PIC450x I've been playing with for years.

 

[skeezix]

I didn't read too much into it, but sounds like they're still suggesting external ram and rom, and using flash as aux; certainly, the ez80 can write to its own flash, anyway (and certainly you can flash it through the zilog debugging cable.) I'm imagining SPI can do it, but I didn't look close enough.

(for my part, just rely on the external bus.. everything else is bonus, for now)

I still think Atmels rule the one end of the spectrum; self sufficient, trivial to set up, pretty performant for what they are, and excellent toolchain support from the avr communities. PIC is pretty solid, but not as well supported for OSS.I mean, unless things have changed, is everyone still using SDCC for open source compiler, and the various shitty Microchip compilers for Windows? (ie: great, a compiler that loses features after the first week or two.. brillant!)

But these ez80s look pretty swank; price comparable to the atmegas (more pricey than some, cheapere than others), but running 20 and 50MHz? Hot damn!

Course, avr8's can be gotten in DIP still.

The TI stuff is pretty swank too, and TI is amazing with samples....

I love that they sent out that key frob a few years back; plug it into usb, and it had the windows toolchain and pdfs and such right there on flash; you could be up and compiling and testing within 5 minutes flat. Genius

I'm slipping into 'order mode' now .. gotta get me some ez80s to fiddle with ASAP, make a final choice about z180 and ez80. (yeah, _thats_ the excuse I'm sticking with.)

jeff

 

[skeezix]

The various QFP adaptors I have now (big pile of them from Thailand for next to nothing) .. donm't have a 100pin that is also 0.5mm spacing; 0.8mm and 0.65 yes, but not 0.5 .. blast! I do have some incoming from HK or somewhere, but theres a few weeks away yet.

.. did find a local guy who is selling some for $2-$4ea though, for the square ones (or $20 for the DIP breadboard kind.. ouch, no way.. I'm cheap!) .. so think I'll go pick up 1-2 of these pricier guys for $2ea (pay more in gas to get there , and order 2 or 3 ez80s to experiment with (digikey,.ca isn't as fast as their US brother, but I can live with a weekend + 2day for them to arrive .

So, next week is ez80 week, to see how well they will play with the STM32.

Then the week after that is Thief 4 and I won't see a soldering iron for awhile

jeff

 

[Asiyura]

I finally resigned to use a deserializer chip. Arduino "layer" on AVR is a pain in the ass when you want to use an I/O port to send/receive data in parallel. I don't own the chip used in the arduino examples, but I do have some old-school CMOS CD4094 ones. I got them because they're basically the opposite of CD4021 that are used in NES/SNES gamepads. So I checked on the net if 4094 are compatible with arduino's shiftOut function… They work like a charm

I got some noise out of one of the AY-3-8910A! But while I was testing its GND wire came loose (my fault, didn't tighten the screw enough). So now the chip seems to play more or less random notes and channel A is either completely silent or keeps playing the same note.

It's kinda sad to kill one of those chips. But well, I still have four more and they're going to be handled far more nicely.

---

Something is missing badly in my stack of electronic parts. So I just ordered a set of 60 pieces with 27 various values ranging from 24kHz to 48MHz. That should cover most of my needs.

I also finally ordered a ST-Link V2 debugger/programmer. I could have gone for those evaluations boards. But since I already have a bunch of STM8/32 in my cupboard, I'd rather try and start from scratch.

 

[skeezix]

Of course, one of the old options I was looking at at the start a year ago .. dual port ram.

Those suckers are expensive; back then I was trying to avoid SMT too, but if you accept QFP80 or QFP100, you get some more options. Still, they're on the order of $30 and up for low quantity.. like $40+ realistically. Ouch. If I didn't have peripheral concerns, that could be a way to go .. ie: say your brain is an avr8 (cheap as dirt) and you're using a 1MB dual port RAM, your costs sort of balance out, and life is easy. But in general, a dpram is just so pricey, its best not to think about it, when you can just do timing games instead

 

[skeezix]

I got some noise out of one of the AY-3-8910A! But while I was testing its GND wire came loose (my fault, didn't tighten the screw enough). So now the chip seems to play more or less random notes and channel A is either completely silent or keeps playing the same note.


It's kinda sad to kill one of those chips. But well, I still have four more and they're going to be handled far more nicely.


I'm finally resigned to use a deserializer chip. Arduino "layer" on AVR is a pain in the ass when you want to use an I/O port to send/receive data in parallel. I don't own any of the one used in the arduino example, but I do have some old-school CMOS CD4094 ones. I got them because they're basically the opposite of CD4021 that are used in NES/SNES gamepads. So I checked on the net if 4094 are compatible with arduino's shiftOut function… They work like a charm


---


Something is missing badly in my stack of electronic parts. So I just ordered a set of 60 pieces with 27 various values ranging from 24kHz to 48MHz. That should cover most of my needs.


I also finally ordered a ST-Link V2 debugger/programmer. I could have gone for those evaluations boards. But since I already have a bunch of STM8/32 in my cupboard, I'd rather try and start from scratch.

You'd think if the GND jumped out, it'd be okay .. the circuit would just fail, not blow the current out through one of the other lines or fry it.. but at that microinstant of time, who knows; or your gnd hit one of the other rails or lines when it flew out I guess. Sad day

I tell my kids.. when they get a scratch.. 'bet you were having fun' and 'if you don't get a scratch her eor there, you're not really having fun', that sort; you gotta risk falling if you want to run, right? So good on you Kill some pieces, its all good. It died in the line of duty

.. I dunno about those CD chips; why not just a shift register? They're pretty cheap usually, and you _need_ a few of those in the toolbox!

Nice, re: stlink; good kit. The dev boards might be the way to go in  way, since you can get them for what, $10 and include an stlink on them. But the dedicated unit is a nice little guy, solid pinouts etc, no screwing around. I like it. The STM32 is a little hairy to get into, but now that I know how to do it, its trivial But it seems when you're coding it, every other thing will not work 'the way you'd expect'; an avr or PIC just works I find.. good design and good samples for sure, but .. you throw some code in, and voila. I find the STM32, I get it wrong the first 5 times at least, first But badass chips, for sure.

..

what did you get a kit of 60 of? crystals?

jeff

 

[skeezix]

Sweet, found a nice RAM on digikey ..

http://www.digikey.ca/product-search/en?WT.z_header=search_go&lang=en&site=ca&keywords=1450-1017-ND&x=0&y=0&formaction=on

DIP!

55ns is pretty good (but not great .. they vary from 10ns to 150ns more or less, so this is middleground; but sometimes the too-fast guys are trouble, noise impacting them.)

Parallel of course (not serial sillyness)

2.7V-5.5V tolerent, so works with everything I care about.

And cheap.. $2ea!

The eeproms are what get you for DIP, but people can swap in any number of parts, who cares; any arcade fingerboard (I'll make some to sell) will do as an eeprom->zikzak cart adaptor, so any eeprom that works will do fine.

Ordered me some ez80's ($5/ea is not too bad) and some of these RAMs to trial out

jeff

 

[panik]

Really, I should put together a board layout for a couple adaptors; can't be that hard to make a LQFP100 adaptor and then just have one of those boardhouses knock it out, see if it works.

If you're going to make the adaptors yourself, consider room for soldering pullup/down resistors, decoupling caps and what not on the bottom of the board.

Like this '64 pin LQFP-to-DIP PCB': http://www.voti.nl/shop/catalog.html (click to 'PCB's' -> 'PCB-09'). The outer row connect to ground, the inner row to vcc. Super handy!

 

[Asiyura]

'bet you were having fun' and 'if you don't get a scratch her eor there, you're not really having fun'

Indeed

I dunno about those CD chips; why not just a shift register?

4094 chips are old school CMOS shift registers, I was not sure that I could use those without lot of changes in the source code I've found. But even if they don't have the same pinout as the 74hc595, they're working exactly the same.

But the dedicated unit is a nice little guy, solid pinouts etc, no screwing around. I like it.

Well, that's why I chose the standalone unit. And because I could have one for about 27€ (with shipping), not that much more than an evaluation board At worst, I'll buy a cheap evaluation board later. But I'll still have a solid tool far more convenient than a bare circuit board.

what did you get a kit of 60 of? crystals?

Yes crystal oscillators, I paid less than 9€ for the whole kit.

If you're going to make the adaptors yourself, consider room for soldering pullup/down resistors, decoupling caps and what not on the bottom of the board.

Pads for the oscillator (if needed) could be useful too.

 

[panik]

If you're going to make the adaptors yourself, consider room for soldering pullup/down resistors, decoupling caps and what not on the bottom of the board.

Pads for the oscillator (if needed) could be useful too.

True, but for different chips the oscillator needs to be on different pins. And an adaptor for a specific chip wouldn't need all the rows of pads. Only on the pins that need them. That would turn it into a breakout board (which is useful in itself), but not a generic adaptor.

 

[skeezix]

You know, maybe just skip timing games .. Was going to interleave clocks so both gou and z80 read/write ram at same time; provided the wait states and ram timings don't get in the way this can work great (see C64..) .. On the other there is a certain complexity required .. You need a couple buffer chips to ensure you're not bus colliding - both raising write at same time and frying everything..


Might as well just use the z80 bus control ..


Gpu enters vblank


Gpu signals BusReq


Gpu waits ... (Since much faster)


Z80 raised BusAck when it stops needing bus for current opcodes


Z80 waits...


Gpu receives interupt on BusAck, starts reading memory until vblank exits


Gpu copies ram to internal framebuffer fast as it can .. Be nice if it could grab whole frame and thus let z80 do pixel framebuffer in rM


Gpu releases BusReq


Z80 continues


Gpu renders vga


Course the side effect here is z80 essentially paused during each vblank ..


It'll allbe moddable so hou could use i2c between z80 and gpu, or snother memory strategy or do clock interleaving, or .. Etc


Zikzak flexible

 

[skeezix]

Okay so looks like ez80 defaults to internal flash (ie: it is enabled and at 0x00); you can disable it and remap it to another address. (Will have to see if there are fuses in the flash to change those defaults .. Otherwise need a very smll bootloader or bios..)


The upside is .. During development of small apps, can use a jtag/zilog cable to program the flash, without removing the cart. I was mulling over some switching circuit so could put a zikburner on board, or perhaps on-cart, or any nunber of crazy ideas as I'm sure yanking out the cart every compile will get old fast..


But with the flash we should be able to just hit go, hit reset, watch. Plus live debugging.


Problems, cUse there always are some..


- sounds like sdcc and zd88 are crummy for ez80 features


- you Can run ZDSII zilog toolchain under Wine..


- the zilog usb cable does not work with linux afaik


- the zilog ethernet and serial based cables do work afaik (an ethernet plug proframmer .. Will wonders never cease); the serial canle seems hard to get, and the ethernet one is $100 .. Oww


So sounds like building code in wine, then using expensive cables ... (And buying another ethernet card..), or leaving a indows laptop on :/ it also sounds like ZDSII is a subpar (buggy) compiler.


I need to tell myself again why I'm requiring a z80 on there when coukd use a damned a avr or 6502 or whatever


Course can just use sdcc or zd888 in z80 mode..


.. But how to burn ..


Anyway screamy kids

 

[skeezix]

OKay, even sicker idea.

You can program the ez80 over "ZDI" (Zilog Debug Interface), or other nefarious means.

I'm already since 6mo ago planning to drive the clocks on the brain chips (z80) from the gpu.. so the brain can ask the gpu to turn up/down its clock rate, in case you want to do that; but also so the gpu can, if it needs to, suspend the clock

Now, I'm assuming some number of folks, who have a zikzak, to have an STM32 programmer, so they can reflash the gpu code. They may also want a eeprom burner, or zikburner, to make carts with. But if you just have the stm32 programmer and no zikburner, we could hook up the gpu to the ez80 in this idea, and reflash it from there. Sort of like how some people use an arduino as an arduino or avr programmer, in a pinch; arduino is readily available, so use it to talk SPI to another one and flash it. (arduino is pricey, but everyone has one right?

So likewise here.. flash your gpu into proxy mode, and then use a command line tool that talks to it, to reflash the ez80; or flash something into the gpu, which then flashes the ez80 automatically, or something. Then flash the gpu back to a gpu mode of operation.

Sort of a goofy way of doing things, but could be worth doing, to save on $$. And as a neat hack

I'll never remember to hook up all these things on the schematic, so lotsd of things for peopel to hack on if I keep the header pins exposed

jeff