Microcontrollers (MCU) - Buying Advice

1. Check what the application really needs to do or might need to do. 2. Once you select an architecture you will probably stick with it for a while. 3. Better solutions might exist afterwards but knowing better a medium CPU is better than using an not well understood better architecture. 4. Get the Toolchain and use it for a while. 5. See if you can find code examples on the internet or the microcontroller company website. You might need it.

Start by making sure you understand the functional requirement of the design fully before selecting a micro. Reduces risk of placing an overly expensive part in the design. Same goes for under specifying the part. The available toolchain for the micro you wish to use should be looked at carefully. Depending on development budget, certain toolchains will render a micro unviable commercially.

Selection of MCU is beyond the part price, the consideration should inclusive the software packages (SDK) and development supports, service & maintenance supports rendered.

In using Microcontroller properly elaborate your product or design so that you can easily choose (MCU), Number of I/O, Analog channel requirement, Clock Speed, Cost factor

- More research on needed features to select most suitable MCU. - Contact electronic distributors for price and availability. - Warn about goods from Chinese origin.

My suggestion is for people willing to use a RTOS, I suggest to take a look on NuttX, this RTOS implements almost all POSIX API and many features found on Linux.

Always define your specs before buying, as migrating code to another brand or module type might give you a headache!

Just buy a robust microcontroller with a fast clock speed and big Internal RAM & ROM size with a cheap price :-)

Go for the one with a lot of pins with different functions and mostly 32 bit if you are comfortable with ARM.

Selection of Microcontrollers to be careful, check free development sources are available

With microcontrollers you can do anything, they are extremely versatile

Must be ready to study a lot of technical literature - both HW and SW

Check for good customer service which include after sale service .

Look for : good repetition company ease of use and develop

Development tools and more important than the actual MCU

You must use the Atmel microcontroller satisfied

Go through the features ....rom and pins

Use PIC's and PIC Basic to get started

The price is not the first concern

Use a good simulator first!

They advice me to use avr

Sorry. I don't have.

Look for tools free

1. Do not hear the buzz words (clk rate, MIPS etc) from the microcontroller companies. The best way to determine performance is: a. By the internal hardware architecture b. By your own testing in relevance to your application. 2. Some times we see how easy is to endorse a new architecture but in the end this architecture may prove limiting in advanced programming. See the forest and not the tree when you select a new architecture. 3. To use or not use RTOS? My experience says that the critical limit of this difficult to answer question is: a. Is your MCU able to make a round robin loop under worst case conditions, meet it's timing constraints with a proper safety margin? If yes then probably you don't need to add the complexity of an RTOS. b. A second criteria depends of how many threads you need to service and if your application will be far more easy to develop using multi-tasking. Then you should go with an RTOS.

In choosing a microcontroller you should check the situation where the controls are placed. Things that should be checked are temperature and vibration. If you select a microcontroller with a difficult programming. make sure spare parts are sold, easy reference in the search.

Flexibility and scalability are very crucial factors to be considered when selecting MCU products. Should avoid a product which is designed in too narrow specification as this will limit the future expansion of these MCUs for new applications down the road.

Always check end of life cycle for the chosen uC, as it can be discontinued and replaced with a module with different options, and leave you stuck with old hardware. Happened to me once with Motorola (68HCXX family).

Read data sheet carefully prior to supporting hardware design. For example, many devices have multiplex peripherals so that not all functionality is available at the same time.

Make sure you know whether addresses are big endian or little endian! I lost several days trying to figure out why it was booting from the wrong place.

- Read errata of the MCU first - caution on difference interface such as TTL- CMOS,... - voltage level/threshold on communication signal pins/

Choose an MCU that has sufficient capacity for expansion and preferably offers some alternate approaches to tackling your I/O tasks.

Application Performance requirement has to be checked carefully on Micron controller or Inside Peripheral's Bandwidth, Performance.

Availability of spareparts, 24/7 assistance over calculation of their needs on the project so the PLC far too big.

Read the manual or catalog of microcontroller product. Is it suitable for your application project or not?

For NuttX select MCU with at least 64KB of Flash. It is necessary to fit NuttX and your application

Don't try to save money buying devices with limited resources (RAM, Flash memory etc.)

Make sure you have the latest silicon version, errors have been made in the past.

Prefer high clock speed and less input voltage supply controllers

Rom,default nature of the ports

Not be afraid of difficulties

Use a good simulator first!

Check the datasheets first

Low price means bad MCU ,

Depending of applications

Sorry. I don't have.

Emulation kit..

Not really