What is the benefit in learning ARM Cortex and FPGA's?

[andyturk]

Nice first post, kshitij!

[Arrow]

Nice first post, kshitij!

First post with alot of knowledge!!! welcome!!!!     

Question:
There are many companies that make ARM processors, which should I go for?

[kshitij]

There are many companies that make ARM processors, which should I go for?

Honestly, use whatever works out best for you. There are so many variants from different companies out there, that if I suggest one, people will counter with a long list of their version of better chipsets. 

If possible, do try and get a cheap eval kit, and, a good book (quite a few of them show up on an "arm cortex" search on Amazon). I googled some EK's for you,

1) http://www.arm.com/support/university/development-platforms/cortex-m3-development-platforms.php
2) http://www.google.co.in/search?q=arm+cortex+olimex&aq=f&oq=arm+cortex+olimex
3) http://microcontrollershop.com/default.php?cPath=154_170_356
4) http://www.lpctools.com/evaluation.boards.kits.lpc13xx.cortex.m3.aspx

Go for the cheapest one (unless, ofc, you're funded )
Another option, get a free chipset sample from the manufacturer , and solder it onto a cheap header board (several can be found on Digikey ). If you're in college, see if some professor knows a local electronics dealer, or if he can get enrolled in a  University program with manufacturers. I know Atmel  & TI send some free kits for a University program affiliate (atleast in US).

[TheDirty]

I would definitely narrow down the selection to those manufacturers that are putting out cheap dev boards with debuggers and are targetting lower cost developers.

You really have 3 selections for Cortex-M with cheap hobby focused or easy access development.
Your main 2 are:
NXP LPC has the LPCXpresso development boards.  M3, M0, M4
ST has the STM32 development boards.  M3,  M0, M4F

Both of these guys offer a decent selection both of basic development boards with their JTAG debuggers on board.

You can also go TI, but the only thing they are running right now is the Cortex-M4F with the Stellaris Launchpad.  Selection and availability is pretty scarce.

[Marco]

There's also Freescale Kinetis ... haven't got very far with the board, but this guy has :

http://mcuoneclipse.com/

Long term support, who knows ... but for now they are interesting boards/chips.

[andyturk]

If possible, do try and get a cheap eval kit...

Cheap is good.  I've been using STM32 mcus in my projects mostly because their Discovery line of eval boards are pretty nice. The STM32VLDiscovery is less than $10 USD and gets you breadboard-ready hacking platform with on-board debugging that only needs USB for power. Throw in GCC, Open OCD and a few hours of your time, and you're up and running with ARM.

The disco boards are cheap from ST, but the VL has a wimpy processor. The mcu that comes on the board only has 8K of RAM. Fortunately, ST processors are generally pin-compatible, so you can whip out your hot air gun, desolder the original chip and drop in a STM32F103RGT6 monster ($12 in single quantity) with 1M of flash and 96K of RAM.

[westfw]

Does it has an completely new assembly language or are they like the AVR and the MCS51?

The AVR and MCS51 don't have the same assembly language.  The ARM assembler is not particularly any more different than the differences between AVR and 8051.  The most popular assembler for ARM (perhaps the only one?) is the Gnu Assembler, which has a lot of commonality even between different architectures (all the pseudo-ops are the same, etc.)  OTOH, it's not my favorite assembler :-(

unlike any other microcontroller I know off you don't need any assembly language to get an ARM Cortex Mx controller to run software written in C.

I don't think I understand why that's important.  It's almost possible on AVR; several AVR chip families initialize the stack pointer to appropriate values, and I've written avr-gcc programs where the only assembler "initialization" was setting up the "known zero" register, which is a compiler optimization that isn't strictly necessary.

[NiHaoMike]

Don't forget the Raspberry Pi, which is very powerful for its price. Also note that nearly all of the phones and tablets out there are also ARM based.

[Neilm]

An FPGA would prototype/replace the ASIC-based signal processing section since it requires very high sampling rates.
                     So , if you intend to work on designing signal processing  routines such as carrier recovery, adaptive equalization, modulators/demodulators for digital comms, FPGA's provide the fastest route to rapid prototyping. And as long as you have access to all this PHY-based IP,  you can normally implement faster image & video processing routines on them. For eg; target recognition, feature extraction etc. FPGA vendors also provide microprocessor cores (like a PowerPC or even ARM) which can used to realize complete physical layer subsystems.

I would also use FPGAs / CPLDs to bridge the gap between an embedded processor and a lot of interface circuits - for example a processor connecting to a bunch of switches, relays and ADCs. Either you have to buy a much more powerful processor to get the physical IO you want, or you put a small CPLD in to interface to all that and use your processor for some else.

Neil

[nctnico]

Are you mad? A CPLD requires programming during manufacturing. Ditto for an FPGA although that could be part of the microcontroller firmware. Either way it adds way more costs than a bigger microcontroller. Not only for manufacturing but also for development.

An FPGA or CPLD is only usefull if you need to handle a lot of data very fast.

[Marco]

An FPGA or CPLD is only usefull if you need to handle a lot of data very fast.

ice40 gives you more than 100 i/o for 5 bucks in singles ... if you really need a ton of i/o it can be interesting.

[nctnico]

Well, a bunch of 74HC595, TPIC6C595, 74HC165 connected to the SPI bus give you any number of I/O without having to route lots of lines across a board. And they are way cheaper per pin than a CPLD.

[Marco]

I don't care about CPLDs, I was talking about the ICE40 ... it is actually in the same range of price per pin.

[jerry507]

You're already programming a micro during manuf, what's one more device? That's a complete red herring.

[jeroen74]

It does add cost and one more thing to maintain. CPLDs usually do not have the same programming interface as the MCU used.

I wouldn't use a CPLD for interfacing to slow I/O stuff like switches and relays.

[nctnico]

You're already programming a micro during manuf, what's one more device? That's a complete red herring.

One more device means connecting a different programmer and waiting for it to be programmed. Secondly someone needs to write the 'code' for the CPLD, have meetings with the firmware programmers about the interface between the uC and CPLD and the CPLD just adds to the amount of code that needs to be documented, maintained, etc. So yes, using a CPLD adds a significant amount of costs to a product.

[jerry507]

I mentioned programming costs alone. It really doesn't cost that much more. The cost of 1 or more programmers, and a pretty small amount of time programming it. I'm not sure why you'd not be programming in a jig, in which case it doesn't even add time to hook it all up.

I assume people are using CPLDs not because they want an IO expander, but because they want some dedicated logic. In that case using std logic is... well, stupid. The CPLD is compression of std logic, so if the design is simple enough to use std logic, use that. Otherwise use a CPLD.

Stating the CPLDs are stupid ALL THE TIME is silly. They obviously have a place, and if it makes sense use one.

[westfw]

You're already programming a micro during manuf, what's one more device?

Also, you can embed FPGA "code" inside your microprocessor object code, so you wind up with only one image to burn, and remove a specialty FPGA config device from the BOM.
(don't get carried away.  I yelled at someone (metaphorically speaking) when they complained that our utility for converting a binary to to a C uint_8_t array broke on something as large as a linux ISO...)

[jeroen74]

Most FPGA don't need a speciality devices. Those Altera EPCS devices are way overpriced and can be replaced by a 25F80 for example for a fraction of the price.