Designing a PCB

One of the things I wanna learn this month is to build hardware circuit on a pcb with commercial CAD software which are used to build circuits. The coolest thing about PCB software is that you can actually simulate a circuit without making the real hardware circuit. and it helps you analyze faults before you produce your circuit. I had designed a small PCB for SPI interface of an MMC/ SD card to a microcontroller. It was easy to design as there was no special circuitry needed for except for a few optional pull up resisters which should be used if the BUS is in open drain mode. If it is in push pull mode then there is no need of using pull up resistors. It all depends on which microcontroller we are using. If we are using a low end microcontroller like a PIC which is cheap we must use a Pull up on the data lines of the SPI bus. On the other hand if we use a High end microcontroller, it may provide options so that we dont need pull-ups. Overall PCB design a must learn thingy if you are into hardware and serious about becoming a hardware engineer.

Nand Flash memory

Nand Flash memory is the latest technology which is happenning recently. We can see such types of memory devices in an I-pod nano from apple. They are compact and very efficient have better write cycle ratio and are way better than hard drives. This is an important issue when it comeos to space.. as in cellphones, digital cameras or robots where it is good to have a memory device which is smaller and lightweight. Samsung is going to launch nand flash memories upto 16gb by the end of 2006. You can read a general introduction to nonvolatile memory here : http://aplawrence.com/Makwana/nonvolmem.html

Also there is an application note from freescale ( motorola ) which is titled, “Non-volatile memory overview”. The freescale website has the pdf file of the article.

I read somewhere that there are 1 inch harddrives on the market to be used in cell phones or digital cameras which can store upto 6 gb of data. This is interesting.. cause the smallest harddrives were about 1.8 inch in size, last year. Toshiba and seagate are manufacturing these devices along with sony.