Thick Film Resistor vs Thin Film Resistor
If you are a system designer, you probably always find that there are two kinds of chip resistor, which are thick film resistor and thin film resistor. The question is, what is the difference between thick film resistor and thin film resistor?
Found
this site that explains the difference.
Cyclone series continues ...
Finally, Altera launched Cyclone III, after a couple of months lauching Stratix III.
Of course, success stories should be continued...
That's why we still see Cyclone III and Stratix III today.
To be honest, I anticipated improvement on the Cyclone III logic elements architecture compared with Cyclone II, such as implementing a 5-input LUT in a logic element. Nonetheless, other improved features are pretty interesting, too. I am particularly excited with M9K, PLL reconfiguration and improved I/O element.
The cost is an important factor when you are evaluating a new device. However, the cost factor is never mentioned in the data sheet or handbook. I am referring to Digikey for cost comparison among all the Cyclone series families. EP3C25 is chosen as benchmark as it is the only Cyclone III FPGA available now. The Cyclone II and Cyclone FPGAs that come closest to this density are EP2C20 and EP1C20, respectively. No doubt, from the table below, Cyclone III is certainly worth considered if you have a new design to start with a low-cost FPGA. At a slightly lower price, you can get a higher performance, same density and twice internal memory size for Cyclone III FPGA, compared with Cyclone II and Cyclone I.
| Cyclone series | EP3C25F256C8NES | EP2C20F256C8 | EP1C20F324C8 |
| Price | $44.80 | $42.70 | $60.00 |
Low power consumption seems to be the highlight for Cyclone III in the Altera marketing slides. Unfortunately, that doesn’t interest me too much as I am not working very much on the portable designs. Anyway, I still hope to use 65-nm Cyclone III and Stratix III parts for my new coming designs.
Can PLL self-locked without "External" input?
I was busy working on something and suddenly a crazy idea came up.
Can a PLL lock itself if I connect a PLL output clock to the PLL input clock on a PCB and both the PLL multiplication and division value is set to 1? I expected the answer is no, of course. But the curiosity kills sometimes. So, I went ahead and did the simple test.
I was using a Cyclone II device. Surprisingly, I saw the PLL locked output signal went high. However, the output signal frequency wasn't the expected frequency (10MHz). I probed at the PLL output clock (which was also connected to the PLL input clock signal), it showed about 420kHz.
So, what is the conclusion of this story? Nothing.
Lattice Now Blogs!
Insteresting! Lattice now blogs! A lots of non-confidential-but-technical information out
there!
It is always nice to see a FPGA vendor takes initiative to provide a platform for their knowledgable engineers to share their experience and knowledge. The good thing is that the knowledge shared is not only limited to Lattice products but all the vendors FPGA.
I know it is not easy for the writers as they now have one more repeatitive task in their long to-do list besides their daily jobs. Anyway, I hope they continue doing this! Bravo to all the writers!
Embed Tclet in Your HTML
Since started this blog, I found out that I need to study a minimum amount of HTML to display my writing correctly. Besides, I can have more control writing in "HTML mode" compared with "Compose mode". For an example, you can't just type the symbol "<" in your blog message, instead, you need to type "<" to display "<" in your blog. Don't get me wrong, I am not trying to show off my HTML skills. In fact, I only have very basic and minimum knowledge about HTML.
Anyway, if I am not wrong (considering myself not a webmaster), it seems like HTML alone doesn't have the ability to let you do real-time programming stuff on your web browser, such as Mozilla Firefox or Internet Explorer. However, it can be done using a plugin.
There are many different types of plugins out there, but I choose to use Tcl applet or
Tclet since I did some study on this language before. (If you've never heard of the Tcl/Tk language before, you can visit
here.) I don't know how to embed a
Tclet properly in blogspot. However, I manage to do it on another
free site. This
Tclet in this free site is to display all the gray code counter results in sequence after you have entered the number of bits your gray code counter is. I don't know how useful it is to you, but it is useful to me because I always forget how the gray code counter increments. Bear in mind that if you are a first-time user or viewer, you need to download and install the
Tcl Web Browser Plugin for free. And, of course, it is SAFE to be installed in your PC. If you haven't installed it yet, you will see a blank square instead of the picture
on the left side
here.
It will be a bit long for me to describe how to embed
Tclet in your HTML code here. The best source is the reference book that I show in
here. Of course, you can look at the HTML code in the
example above. Plenty of funky Tclet examples can also be easily found on web if you are interested to see others. Hope you like it.
Save More Power In Handheld Devices
How to save more power when your CPLD device is in idle mode?
Use a very slow clock to reduce toggle rate? Partially disabling the logic inside the device? Well, why not powering off the device?
I came across this interesting
article by accident and found it a simple yet smart idea to prolong the battery life of a portable handheld devices. In future, if I have the chance to design a portable product with interactive user interface, this idea will surely be the first one to cross my mind.
If for whatever reason, you have to use a FPGA in a battery-operated product, this
article will sure help you more.
OP-AMP Configurations Recall
It has been a while since I last dealed with op-amp. So, it is good to recall some of the most fundamental op-amp configurations, especially when I am dealing with them recently.
In my opinion, op-amp is like logic gates in analog world. You need op-amps to transfer your analog inputs into your desired analog outputs.
The following are some important notes for me, not for you, of course, :)!
| Common Names | Op-Amp Circuits | Transfer Functions |
|---|
| Voltage Follower Amplifier |  | Vout = Vin |
| Inverting Amplifier |  | Vout = -(Rf/Rs)Vin |
| Noninverting Amplifier |  | Vout = (1+R2/R1)Vin |
| Difference Amplifier |  | If R1/R2 = R3/R4,
Vout = (Vin+ - Vin-)(R2/R1) + Vshift |
| Summing Amplifier |  | Vout = (R2/R1)* (V1+V2-V3-V4) |
on the left side here.
