65Org16.x Dev. Board V1.0 using a Spartan 6 XC6LX9-3TQG144

ElEctric_EyE · Post by **ElEctric_EyE** » Tue Aug 16, 2011 5:30 pm

Thanks alot for the tips BDD I really do appreciate them. I have done away with 2 of the other planes I had on top of the board. I did take your advice and use a single ground for the digital and analog.

The 2 filled planes you do see are for the FPGA's 1.2V and 2.5V supplies. No signals pass through or over/above the filled planes. I figured the closer I can get to the power pins with as much copper as possible to the VReg's, that this would reduce noise. Same idea with using slightly thicker .010" traces compared to the .006".
The big via's in the middle are for the main 4.7uF 1.2V & 2.5V bypass cap's. The smaller .031 via's all around the outside edge of the planes are power via's connected to bypass cap's. The 1 arm on the top level (red) is a tap from 2.5V to some JTAG jumpers so I can choose between 3.3V or 2.5V.

Hopefully I can eliminate that 2.5V tap along with alot of extraneous jumpers/resistors around the FPGA PROM. Xilinx's data sheet is abit lacking in explanation, because there are so many voltages each bank can function at and the banks the JTAG must similarly comply. But since I am strictly 3.3V TTL I think I'll be able to get away with eliminating alot of stuff... Even more than the 6502SoC JTAG, but that used a Spartan 3 device, so some experimentation is involved.
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Some more searching led me to this. It is only using 3 resistors, but the voltages are wrong... Will experiment and report back.
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I am seeing 2.5V and 1.2V supplies.
Will solder all the PS bypass caps next retest. Then FPGA bypass caps...

ElEctric_EyE · Post by **ElEctric_EyE** » Wed Aug 17, 2011 5:49 pm

Ok, after soldering all the caps and then soldering the FPGA very carefully! (No solder needed, there was plenty already on the board), I am seeing the shorts from both 1.2V and 2.5V to GND. I did not apply power. Obviously I have some pins hooked up wrong, although I've checked the power pin and GND assignments more than 5 times before manufacture of the board...
I may have to post in the Xilinx forums, if I don't turn up anything.

ElEctric_EyE · Post by **ElEctric_EyE** » Wed Aug 17, 2011 6:55 pm

OMG, I am so stupid. I must forgive myself. Pin 1 orientation was 90degrees off, and I did it twice. What a hack.

BigEd · Post by **BigEd** » Wed Aug 17, 2011 7:00 pm

hey, but you have an explanation now - it's the inexplicable ones which are the worst. Nothing to stop you now!

ElEctric_EyE · Post by **ElEctric_EyE** » Wed Aug 17, 2011 7:17 pm

This is true. I am not too discouraged. I am more disappointed at my oversight... I'm gonna have a few beers and tackle the soldering next week on the final board. It does raise the blood pressure and requires much patience, but I am getting better at that too. Gonna make myself sparse now

BigDumbDinosaur · Post by **BigDumbDinosaur** » Thu Aug 18, 2011 3:30 am

ElEctric_EyE wrote:

OMG, I am so stupid. I must forgive myself. Pin 1 orientation was 90degrees off, and I did it twice. What a hack.

Better than producing smoke clouds in your shop.

ElEctric_EyE · Post by **ElEctric_EyE** » Sat Aug 20, 2011 12:01 am

V1.1 is near completion so we can use the 16Mx16 SDRAM in conjunction with the 65Org16 and the Cirrus 4954 video IC.

For all interested parties, V1.0 (last V1.0 board), I will need 2 consecutive days off (next tue&wed) to solder all needed parts correctly!. The SDRAM will not be able to be tested yet since I got the TSOPII template spacing incorrect.
I do intend to test JTAG as I've said before, also do some tests with the PS2 keyboard interface, the USB to UART interface, and the SPI Flash.
It does sound like it make take awhile, but all I need to prove are that the interfaces work and then to solidify JTAG for the Spartan 6 and finish off V1.1 and then have them produced. I expect this will take maybe another month.

Hopefully all that I'll have to change is the JTAG section. Everything else is very much in order and I am confident in this second refined design so far... I have other ideas, but I'll hold off till this concept solidifies into reality.

GARTHWILSON · Post by **GARTHWILSON** » Sat Aug 20, 2011 6:34 am

ElEctric_Eye, I wanted to respond to this earlier when you were talking about the difficulties of soldering, but I couldn't find the link. Now I've found it. Pololu will make solderpaste stencils from your gerber file, and they're not very expensive either. Solderpaste's shelf life is pretty short, so you'll have to decide if it's worth it.

ElEctric_EyE · Post by **ElEctric_EyE** » Sat Aug 20, 2011 10:01 am

I'll definately check that out. Thank you
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Very nice info there and sparkfun. The cost is just a bit prohibitive for the stage I am at right now. If there seems to be demand for this dev board, this is definately something to consider for a higher production rate. Thanks again Garth!

ElEctric_EyE · Post by **ElEctric_EyE** » Tue Aug 23, 2011 3:28 pm

Today is my day off from work. I spent early morning hours soldering in 0603 bypass caps. I did 7 in 2 minutes! I am progressing. Sure I didn't have to solder them on this defunct board (due to the fact the SDRAM pads are incorrect) in order to get JTAG working, but I thought I'd practice, especially since these cap's are only $.02 each...
Also after soldering them, the Spartan 6, the XCF04 Config PROM, power connector and JTAG connectors, resistance is futile! I mean, heh, I see no resistance between 3.3V,2.5V,1.2V powers and GND. Now to just finalize the JTAG interface. Gonna try this Master Serial setup first and hope ISE sees the S6 and PROM. Then we're off to the races!
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Trying to reinstall ISE12.4... My CMOS battery went out a few weeks ago and almost lost my RAID config, which is where all my main project backups are. Luckily, it reconfigured itself so nothing there was lost. I also was able to reinstall Windows on top of itself on the boot HDD and save alot of files there, but the programs don't seem to work. My first attempt at reinstalling ISE has failed. So tomorrow I'll copy all the rest of the Xilinx project files over to the backup HDDs, format the boot HDD and reinstall Windows then ISE. Sorry for the delay, but I have now come to expect this kind of thing. It's Murphy's law. But all it does is delay me. Hopefully tomorrow afternoon I can report back that the JTAG works.

Also, I am busy converting all V1.1 signal traces from .010 to .006 as has been suggested.

ElEctric_EyE · Post by **ElEctric_EyE** » Wed Aug 24, 2011 6:57 pm

Success! ISE is seeing the PROM and Spartan 6, and I've successfully programmed the PROM. This last V1.0 board is semi-functional at this point. I'm finalizing the JTAG portion of V1.1 board layout using just 2 4.7K pull-up resistors on the INIT_B and PROG_B pins.
Next on the agenda is to test the Microchip MCP2200 USB to UART interface.

ElEctric_EyE · Post by **ElEctric_EyE** » Sat Aug 27, 2011 12:30 am

I've got the Microchip MCP2200 USB to UART Winx86 drivers installed on the laptop along with the config utility. I installed all this yesterday from the their website no problem, (yes it's free).
Today I made some more baby steps and soldered the 20-pin SSOP MCP2200, mini-USB connector, Tx & Rx 1603 LEDs and bypass caps, but no clock signals yet.
Plugged it into the PC and no action. No LEDs, no windows recognition of something being plugged into USB...

I guess I will need the 12MHz main clock at least, to get something working...

Time to solder in the 100MHz main clock and experiment with ISE and Spartan 6 DLL/PLLs next.

ElEctric_EyE · Post by **ElEctric_EyE** » Sun Aug 28, 2011 12:54 am

ElEctric_EyE wrote:
...New SMD soldering station won't be in till thur. Will comment on it soon...

Time for comment... As a SMD soldering station, excellent device. I've used the finest point (1of11) to solder all SMD parts with extreme precision.

As a SMD reworking station, using the hot air to desolder an 8 pin SOIC and a 20 pin SSOP, with temp set on 490F within 1 in of device, it took lees than 10sec to notice a difference in the solder, then the IC's were free soon after. I was very surprised, but I shoudn't have been... The conductors will heat up first, before the die inside the plastic. With this in mind, I would imagine the die inside the larger packages would undergo larger duress, so will the hot air gun covering a larger area with a larger dispersant tip.

At more than $4US for the 100MHz oscillator, I didn't want to lose an IC I knew was functional. Previous attempts at desoldering with the iron and wick, etc., were futile and again the hot air was a most excellent device!

GARTHWILSON · Post by **GARTHWILSON** » Sun Aug 28, 2011 2:46 am

Quote:

As a SMD reworking station, using the hot air to desolder an 8 pin SOIC and a 20 pin SSOP, with temp set on 490F within 1 in of device, it took lees than 10sec to notice a difference in the solder, then the IC's were free soon after. I was very surprised, but I shoudn't have been... The conductors will heat up first, before the die inside the plastic. With this in mind, I would imagine the die inside the larger packages would undergo larger duress,

I don't worry about the die temperature while soldering anymore since in the mid-1980's I worked in applications engineering at a VHF & UHF power transistor manufacturer and actually saw transistor dice operating at temperatures of nearly 700°F. Of course they didn't last very long that way, but it proves that normal soldering temperatures don't damage them...unless the case material is right against the top of the die and there's a chemical interaction there at high temperatures. What I was taking the temperatures of with an infra-red microscope however had no cover at all over the dice. They were brazed down to the metalized substrate. That brazing BTW takes a higher temperature than soldering does.

ElEctric_EyE · Post by **ElEctric_EyE** » Tue Aug 30, 2011 7:37 pm

GARTHWILSON wrote:
I don't worry about the die temperature while soldering anymore since in the mid-1980's I worked in applications engineering at a VHF & UHF power transistor manufacturer and actually saw transistor dice operating at temperatures of nearly 700°F. Of course they didn't last very long that way, but it proves that normal soldering temperatures don't damage them...

This gives me confidence in desoldering and resoldering with the SMD station I bought!

Other notes:
I've abandoned V1.1 of the mainboard, because the design has outgrown the 3.8" x 2.5" limitation set by expressPCB, and using daughterboards would stretch signals out thereby destroying signal integrity. I've found a better supplier thanks to BillO in this thread.

I've wanted to change the USB interface I currently have to an 8-bit parallel interface using the 48-pin QFP FTDI IC. It's a much more flexible device. This would require just a little bit more board space, which has now been exhausted if I were to use the old company. I have new freedoms with this new company for larger board space and more holes. 10 4-layer boards for ~$200 is an excellent deal IMO!

I am thinking 2 Spartan 6's now. 1 containing BigEd's 65Org16.x core, the SDRAM controller core and some hardware directly controlling the CS4956 video data, and possibly a 16-bit Cypress HDD controller I've mentioned before.
The other Spartan 6 is containing Arlet's original NMOS 6502 core controlling all other I/O. That I/O being PS2 for keyboard, I2C for video CS4956 registers, SPI for serial flash, USB to 8bit parallel interface, and the TFT flat panel interface. This core would be running either the Micromon-64 or Supermon-64 as the OS. This is the nucleus of the development board I have envisioned.

Also, just to keep things interesting, I've finally acquired the last pieces to construct an Intel I7-875K system with 2000K FSB 8GB DDR3 and a 60GB SSD drive. This system will be used for optimizing and putting ISE through it's paces. I've been buying pieces here and there for the last year to put this thing together...