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Logic Analyzer Idea

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Cool i found this IC but at futurlec:

HT6264 : HT6264 pdf, HT6264 description, HT6264 datasheets, HT6264 view ::: ALLDATASHEET :::

I put that datasheet there because they have the wrong one up there.

https://www.futurlec.com/Memory/HT6264-70Spr.shtml

With this IC i can do about 14 writes in 1uS (microsecond)

thats 1 write in 70ns (fastest speed)

thats 0.000000070 seconds
or 0.000070 milliseconds
or 0.070 microseconds

Thats pretty fast.

$2 for 8KB (64kB (8k x 8)) aka 8192 Bytes. That should be more than enough. and fast enough.

Thanks for the info dude!
 
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Keep in mind the logging code overhead, that's just your write speed, at the very least you'll need to work the time it takes the port read and loop and compare instructions to execute.
 
yeah i know. If my readings go up to every 2us. Then i need to have it ready to read again. So i can read and leave a 200-300ns overhead this way i can be sure to read the next one in time and stuff.

10 MIPS = 100ns Instructions
20 MIPS = 50ns Instructions

So im looking at a 10 MIP now i own a 18F4620. If i use that then i should be able to use about 30 instruction cycles and still have a 500ns overhead.
 
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Im not sure but i just made this in Notepad and it looks ok to me lol:

Code:
S = Seconds
MS = Milliseconds
US = MicroSeconds
NS = NanoSeconds
MIPS = Million Instructions Per Second ( (Mhz / 4 ) for pic i think)

S -MS -US -NS  =    MIPS
---------------------------
0.000 001 000  =  1,000,000
0.000 000 500  =  2,000,000
0.000 000 250  =  4,000,000
0.000 000 166  =  6,000,000
0.000 000 125  =  8,000,000
0.000 000 100  = 10,000,000
0.000 000 083  = 12,000,000
0.000 000 071  = 14,000,000
0.000 000 062  = 16,000,000
0.000 000 055  = 18,000,000
0.000 000 050  = 20,000,000
 
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Ill probably get the newer PIC18F46k20 since it can do 16MIPS. I was thinking about AVR/ARM

I was wanting to get into ARM for a while but no money at all lol So i might play with AvR since they are cheap.

Might get ATMEGA88 from :
https://www.dipmicro.com/store/ATMEGA88-20PU.

20MIPS and Cheap! and i got a AVR programmer here somewhere so heh.
 
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AVR's are good for high speed I/O 16mips even on older models at 16mhz, no PLL required.
 
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I wouldn't go with ARM7 until you really need to. It's fun and all, but it can be overly complicated.

I would think you would want something with direct USB support... and possibly a hardware external SRAM interface. I haven't worked with AVR's or PIC's, so I can't offer any suggestions.
 
Hey Mark yeah i do think a ARM is a overkill too lol but was voicing my thoughts only lol i wouldnt pay $8 fo a IC and use it for something simple lol

I might go with AVRs i always like the way the datasheet looks lol also that little ATMEL lettering is cool lol. (of course not my only reasons)

Cheap, FAST, Cheap lol and well rounded with a descent community.

Since i will be using a 20MIPS AVR which is 50nS for a instruction i wouldnt want something where i would be needing a delay so 50nS and below timing on a SRAM is great.

3v0 thats a awesome find!!! Thanks a bunch.

I found this : ($2.60)
IS62C1024AL-35QLI

1Mbit = 128KB = 128,000 Bytes which is way better than a 1024Byte Eeprom lol
 
eeprom is bad to store data like that in anyways, it has a finite number of write cycles, sram doesn't. It is volitile memory though, but in this case that doesn't matter.
 
yeah true. Ill make sure to clear some memory as soon as power is applied and after ever trigger and complete transmission of data to PC. This way i get no false data or anything like that.

Ima save some money for a AVR Dragon. I looked all day and cant find my cheap Parallel programmer so heh ill get a nice USB one. Might take about a week.
 
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You shouldn't get any false data, you're just bulk dumping to the memory, all you need is index bytes to indicate the last byte that was written, when you start a new trace reset the index bytes to zero. The Dragon's look really nice, though you have to keep in mind the come with absolutly no headers on them so you have to solder your own. I have an STK500 still, which sucks cause this machine doesn't have any serial ports on it.
 
Why not add a LCD to it and make a stand alone logic analyser?

I've got some 240x128 LCDs here with nice large screen, and simple enough parallel interface. A PIC based logic analyser has been on my to-do list for ages.

You could even use a 20x4 test LCD and the 8 internal custom characters, that would be ok to display 4 serial bytes, one on each line.
 
A LCD would be to small for the info i will be displaying. Hence the PC side is for mostly converting the data and displaying it on the screen. Will also try to make a nice save function. Not sure about printing or anything like that. Even tho it would be nice heh

I just ordered a overstock of headers from my fav store of all (DipMicro). I have a bunch coming and some other stuff also. I will order some AVRs this week and the AVR Dragon next week.

I will of course make a nice 16 bit address index. This way i can set the end address when done writing. Then have it read from 0x0000 to the end ex: 0x02FF and send those bytes out VIA usb or UART. Maybe that "FT232RL" in a Self Powered Configuration.

Yeah most likely that. I dont want to program a PIC for USB since it will use alot of resources. I rather have another IC to control it all and save huge headaches.
 
Parallel fifo

May i sugest the use of a FIFO buffer, using an independent cristal with selectable prescaler, like
multiplexing the outputs of a 4017, in order to obtain required sample rate ( four bits selection, four PIC outputs).
I have heard of Maxim having some programable oscilators. i dont know if they´re usable at these speeds. i really don´t remember.

Some FIFO´s provide flags for Full, Almost Full, Half Full, Almost Empty and Empty.
This could drive the INT pin of the PIC, iniciating USB burst mode to the PC.

Cypress has some nice FIFO´s in 32 tqfp at 15ns. this is 66MHz. seems enough.

for now i can not absolutly do the USB part of such a device.

I´de love to hear from you.

Best Regards,
Hugo Ferreira
Portugal
 
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