Z8, LCD etc.

routed LCD,Z8 and FT245R.

 

analog inputs

:S

missed one thing: i did fix the JTAG chain.
I did fix bypass caps for the ic's.

Datasheet for AD9958 does not document bypass caps. I used 0.1uF for every vdd pin and 0.2 uF for DVDD_IO (logic level reference - 3.3V).

Status update

Installed xilinx ISE 6.3 and found out my o/s (win2003) does not support it. Fortunately I could integrate Altium with ise and control the digilent s3 board I have. (Took me 2 days)

Altium is great for FPGA designing except for one major inconvenience - no graphical support for state machines. So I had to learn to code an fsm in vhdl. Pretty touchy - but once u get the hang of it its good cos u knw exactly what is happening to your signals.

Oh yes, i did interface my s3 board to altium! altium has some cool features like live JTAG scanning, so now i can monitor my FPGA pin states while the board is online. Altium has a soft core logic analyzer too (works through the JTAG chain). Means no longer i need to simulate my design using modelsim.

Except for these - PCB is still a mess. No comm with fabricator - no info on pcb specs.

draft pcb for SMPS

Here is how it looks.

Top layer:


Bottom layer:
Together:


I placed vias "on" some of the smd pads.

samples

I requested samples of all 4 of my AD chips and the Z8 ucontroller a few weeks back. And as expected, i havent received any reply.

This means i will probably have to buy them.

The dark alternate universe of printed circuit boards

Things to consider before venturing into the PCB world.

1. Single layer / Double layer? - check with fabricator.
2. Size? - check with a teacher.
3. If double layer, ground plane? - check with a teacher.
4. plated through holes ? - check with fabricator.
5. Stencil? - check with fabricator.
6. Silk Screen? - check with fabricator.
7. Solder mask? - check with fabricator.
8. minimum via/hole width? - check with fabricator.

After much deliberation over the past month (:D) - I decided on

1. power tracks - 50 mils
2. signal tracks - 25 mils
3. track to track spacing - 10 mils at least

Fabricator confirmed he can supply 10/10 boards.