I see what you're saying, but on most forums I see people referring to a PIC as being unpipelined because it takes 4 clock cycles to complete 1 instruction cycle, and an AVR is pipelined because it takes only 1 clock cycle to complete 1 instruction cycle. But after re-reading ben's post and finding out that the PIC is indeed pipelined, I'm kinda lost at what those who are saying the PIC is unpipelined are referring to (hence the links in my previous post).

Clearly they don't know what pipelined means in regards to processor architecture or ben is incorrect in his statement that the PIC is pipelined.

I looked it up; both the PIC and the AVR use a 2-stage pipeline (first stage is fetching an instruction; second stage is executing said instruction, and while an instruction is executing it is also grabbing the next instruction to execute). So now I wonder why so many people incorrectly refer to the PIC as not being pipelined? (I'm guessing since both the PIC and AVR are pipelined, it must be something else in their architecture that allows the AVR to process 1 instruction per clock cycle whereas a PIC takes 4 clock cycles to complete 1 instruction cycle )

Also I'm a little confused as to how the PIC and AVR are only 2 stages; how can you just "fetch and execute" without decoding & storing? Or do they fall under fetch and execute?

They probably perform the latter four steps of the MIPS-style pipeline (decode, execute, memory, writeback) during the second part, and only the fetch is in the first part. Unless decode is grouped with fetch?

The pipeline doesn't determine IPC. That is just a performance advantage of the underlying architecture.

I figured it out; what most people are referring to as "unpipelined" and "pipelined" are actually serial pipelines for the PIC family and parallel pipelines for the AVR family.

PIC Datasheet (Take a look at 3.2 Instruction Flow/Pipelining on pg. 10)
http://ww1.microchip.com/downloads/en/devicedoc/30430c.pdf

Each instruction cycle is split up into 4 clock cycles, Q1-4. When a PIC first powers up it executes only one fetch cycle (no execute cycle). In the second instruction cycle 2 things happen at once; in the fetch cycle (stage 1 of the pipeline) during Q1 the program counter is incremented by 1, and by Q4 the instruction is retrieved from memory and moved into the instruction register. As for the execute cycle (stage 2 of the pipeline), during Q1 the instruction to be executed is latched (again?) into the instruction register, then data memory is read in Q2, stuff happens in Q3, and then data memory is written in Q4. Having to complete each step in a separate clock cycle is what makes it a "serial pipeline".

AVR Datasheet (Take a look at AVR CPU Core, especially pg. 14 Figure 6)
http://atmel.com/dyn/resources/prod_documents/doc2486.pdf

On an AVR there are major architectural improvements, especially for the ALU and how it accesses registers. For pipelining, stage 1 fetches and stage 2 executes instructions all in 1 clock cycle. (to really understand the parallelism of this pipelining and the other improvements to AVR's architecture over that of the PIC read the above section in datasheet posted above).

Here's some progress I've made on the kit:



That is the temporary serial port programmer for programming the 18F2550 so that it can be used in a more permanent USB programmer (when the LED is on the 18F2550 is being programmed).

Very nice, and interesting use of an animated GIF as a video-display feature. Any progress on sourcing the microcontrollers?

Newark has all of the microcontrollers in stock except for the 18F4550, which I plan to replace with an 18F2550 (pretty much same specs, just less code space). Once I get the USB programmer built and verified working with the chips in the kit then I'll post a final parts list for everyone to buy

OK, sounds like a plan. Out of curiosity, how much less code space? How much does the 18F4550 have compared to the 18F2550?

My bad I meant I/O pins (the 18F2450 has less code space (24K) than the 18F4550 (32K)).

Take a look at the bottom of page 3: http://ww1.microchip.com/downloads/en/devicedoc/39632b.pdf

How's the kit coming along? Btw, my teacher claims we'll be getting our electronics "kits" (dunno what'll actually be included in it...) next week. I just want to get my hands on a breadboard and some electronics and start fiddling

Right now I'm working on getting the USB programmer working; once that's complete I'll post up a final kit list for everyone to order

Excellent, looking forward to that. Adn magicdanw, you should post up the contents on your kit when you get it.

I should be getting my kit within an hour....suspense.....SUSPENSE!!!!

Oh, btw, I'm sitting next to Super Speler in class right now. How crazy is that?

Update: Aaaaan the results are in! I've got a breadboard, various leds, a battery pack, and two chips. One is the ATTINY2313V, and the other is a MAX2321N (it looks like this has to to with cell phones? wtf?)

And, there's no programmer in the kit. I suppose we'll have to use ones in the lab room, meaning I can't mess around at home without buying my own

The programmer that I'm working on (will continue working on once finals are over ) will allow you to program both PICs and AVRs that are in the kit; as for the MAX2321N, I'm pretty sure that's just another RS232 - TTL level shifter; I'll dig up a datasheet for you.

EDIT: It seems the part you have is a MAX232IN, not MAX2321N (the MAX232IN, the part you have, is a MAX232 in a 16-pin Dual In-line Package (DIP) with industrial temperature specs): www.datasheetcatalog.org/datasheet/texasinstruments/max232.pdf

Did you guys know that you knew each other before?

Good stuff, what do you plan to build with your kit?

We knew that we went to the same school, and realized we were in the same class on Revsoft. Oh, and was your question about my kit or the one Dev'r is putting together? Because mine all depends on what we're assigned in class, as I have no usb programmer of my own

Hey Ultimate, did you give up on the kit and projects? I was looking forward to them

Sorry about not updating this; based on everyone's current level of expendable cash (including my own), I've had to put this off for a few months; hopefully after I get some $$$ for the fall I'll be able to pick this up again