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Messages - anton.todorov

4
Bus Pirate Support / Re: Why isn't my scope seeing the Bus Pirate signals?
In another not related to buspirate project(seeed's Stalker board) I found that 10k pullup resistors source too weak pullup on CLK line and even the onboard I2C devices do not work as expected. Later searching for explanation I found this research: http://http://dsscircuits.com/articles/effects-of-varying-i2c-pull-up-resistors.html

On my BP (v3a) I do not have this problems but using external pullup resistors should solve the case.
5
Bus Pirate Development / Parallel read/write extension card?
Following another thread I started thinking about BusPirate extension card that will allow read/write to NAND chips. Probably it will be slower than dedicated(more expensive) devices like ProgSkeet...

BusPirate is the king in the serial IO world(at least for me) with an extension card it will step in the Parallel world too.

So what buffers are suitable?

Best Regards,
Anton
7
Open Bench Logic Sniffer / Re: OBLS update not working, ACT not lit
What hex file do you load with PicKit2? There is a bootloader hex and firmware hex. If you try writing firmware directly I am not sure it will work. Try to load bootloader with pickit2 then firmware&bitstream via USB. Try as guide http://http://dangerousprototypes.com/2010/06/15/open-logic-sniffer-bootloader-rescue/, but instead of buspirate use pickit2 to write the booloader...

Edit: Take care what is your crystal 16MHz or 20MHz and choose the right bootloader!
8
General discussion / Re: Possible Eagle license giveaway? You decide.
I think the best project to give such license is to someone willing to create something like OBLS XXL* with largest spartan3e fpga possible for most memory depth. I do not look at xilinx docs, but if it uses only 2 rows of balls at the edges of BGA it is possible with 2 layer design but 4 layer is better IMO.

(*) the OBLS XL is reserved in my mind for the 500 gates fpga...
9
General discussion / Re: AMTECH NC-559-ASM solder paste
Well after some experience with ordering 'soldering paste' and receiving flux at density of paste I do not think 'solder paste' is solder+flux any more... It is strange that it is USA product and also have a naming issues common on china market - try searching for "solder(ing) paste" at DX. So now I order from DX only if can see a picture with opened container and there is greyish thing inside...
Try the Lodestar paste - is is still not Christmas rush so I think it will arrive faster and it is cold enough to travel at preferred low temperatures(I agree we do not know how it is stored at china anyway...). It is sealed under the cap but it is possible to evaporate the liquid and to become more dense. It is true it needs more heating with hot air but with soldering iron is OK. I am new in the hot air soldering world so maybe I need some more experience. I populated about 180 components (most of them 0603) on a PCB in a few hours.  Just apply some solder (I use syringe with dremel cutted needle) on one pad, solder SMD then apply on the other pad and solder it too. I use two steps instead of one because without stencil it is hard to apply small enough drop of paste and when you place smd it is possible to rest some paste underneath and make short.

On mass production it is common to save each gram of any product involved, so they apply paste only where it is needed with stencil. Just imagine the situation where you should solder high density BGA using only the solder balls - no more solder just flux...

About profiles I think it is multicomponent flux that is activating different components at different temperatures...

edit:
If it is not grey-ish and can't see micro balls under magnifier I bet it is flux.
10
General discussion / Re: AMTECH NC-559-ASM solder paste
I think it is flux only. The linked PDF says it is used as inner fill in solder wires. I am impressed by this solder paste - it is cheap and make shiny solders. It is important to keep it cool to last longer. I do not have spare refrigerator so I pack it in nested boxes as russian doll and keep it in the kitchen refrigerator. Some people are mixing it with this flux to make it more liquid.

I also have this paste but still not opened it(waiting in the fridge to last the previous mentioned one).
11
General discussion / Re: Entropy
Hell no!
I am crossing fingers to smoothly pass Bulgaria. I have a lot of work that is already screwed up enough! ;)
12
Bus Pirate Support / Re: I2C 24LC256 Help Please
connect to buspirate:
chip pin -- buspirate pin(s)
(4)VSS -- GND
(5)SDA -- MOSI
(6)SCL -- CLK
(8)VCC -- +5v and Vpullup

All other pins leave floating

Use i2c address scan macro to find at what address the chip will respond.
13
Open Bench Logic Sniffer / Re: Triggers on frequency 10 kHz for UART
Your setup expect to have 'high' level on pin 6 and 7 and 'low' on all other masked with '1' pins. All other pins that are floating it is common to have noise on them. So try one of these:
a) in the trigger mask only desired pins - in your case pins 6 and 7.
b) pull to ground all other unused but masked in the trigger pins.

Anton
15
Bus Pirate Support / Re: Binary mode - write-then-read
ok, figured out... nothing is sent, so when reading after write if first byte is 0x00 all next is garbage (if anything)
Now i can read deviceID, manifacturer id etc... lets write some code to do dump, then to write... ( I'm trying to rescue TP-link WR740N - bricked by flashing kernel that does not support this eeprrom, can't brake uboot via serial too...)

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