Help in MCU selection

[mr_byte31]

Hi All,

I need your help to select a MCU for a project to display a picture from USB stick to a LCD computer monitor.

Below I list the most important requirements of the project:
-interface with USB stick (read only is required)
-Interface with VGA or HDMI to display on LCD monitor
-4 channels A/D convertor (optional requirements)


Did anybody played around with similar requirements?

[kreutz]

I guess this is some kind of school project.
There are  a few examples of  similar projects using STM32 Arm processors (using LCD and SDcards) and, since you want a VGA output, you can also check the STM32 based  VGA projects on the web  for some tips. Modifying one of those SDcards' project to use a USB stick is not a difficult task, look into the ST HAL examples.

[witsanukai]

The easy way, try on R-PI, USB ready and HDMI ready can develope by alot of computer programming too, SCRATCH, Phyton and alot.

[pickit2]

I like Pie. one board solution.

[str67]

I agree completely!

Do not use ARM-M3/4 or even smaller architectures as long as you are not planning to go into mass production with your device!
Having a robust and accessible (Keyboard, LAN) operating system like Linux on your RPi or similar radically eases and speeds up your work!

BR,
str

[mr_byte31]

R-PI seems a very easy solution. I like the idea but for me it is like a small computer
I would like to stick to micro-controller. I made searches on STM32 and I was amazed about its clock speed and performance !

Just one more question, isn't there any micro-controller with FFT accelerator ?  this will help a lot in our project.
I know that I can use fft libs but this is just a question for my knowledge

[witsanukai]

STM32 with TFT LCD function and DSP you may need to try by STM32F4X9 series, or try with STM32F411 nucleo will more easy to find and buy at store.

[pickit2]

the R&D dept at my last place of employment bought into the STM32F4X9 family, the devel-board with TFT display cost £300 plus.
there is not many cheap options for a one off. I have just been given a Pi 3 from the workshop of above company, it is reported 10 times faster than the other pi's. you can get one for less than £30 inc.

[GroundPlaneLoop]

I personally would take some highend STM32 if it should be a bare metal design. But today are available RPi, BeagleBone, various chinese clone boards with Allwiner or other phone ARM based multi core SoC for a very low price. The support is not the best, i have to admit, but the development is pretty easy with linux, Qt, and similar tools. The disadvantage is long boot time, but this can be improved by removing unnneeded stuff and so on. Most of these boards unfortunately use MicroSD card for storage, whis is a serious reliability problem. I have very bad experience with problems caused by card corruption. If you can, choose something with an EMMC flash, they are faster and more reliable. The SD card can then be used only for storage / non critical stuff. Be aware that many cheaper boards are improperly designed - fixed core voltage instead of i2c programmable PSU, some have unpractical connector layouts, I prefer pin headers, where all important signals are available.
I experimeted with orange pi nano, it has HDMI out, but i could not get it working, Armbian ran well, power consumption was acceptable...of course USB and some I2C/SPI GPIO with direct linux support of many devices.

Some italian manufacturer (I cant remember now) makes industrial SO-DIMM modules, ARM or iMX6, industrial temp range, but very pricey. My informations are about a half year old, try to look up at chinese markets, you have to select carefully, but the price/capability ratio is very good. My module cost about the same as an decent MCU development kit.

But as I said, the easy development is the shiny side, the long boot and lower reliability is the other side of the coin.

Yes, and you really can use those board without OS, only you have to study the entire datasheet of the SOC and make some RTOS or so. This is not the way to go :-)

[leptro]

raspberry pi zerow could also be a good way.

I have personnaly planned to use them for a Wireless display solution but wait for avaibility.

Regards.

[h0nk]

Hello mr_byte31,

Just one more question, isn't there any micro-controller with FFT accelerator ?  this will help a lot in our project.
I know that I can use fft libs but this is just a question for my knowledge

Some DSP's made by TI include a FFT hardware accelerator.
Details You will find in the Application Report
"FFT Implementation on the TMS320VC5505, TMS320C5505, and TMS320C5515 DSPs".

http://www.ti.com/lit/pdf/SPRABB6

If this link is not working for You, search for SPRABB6A.PDF.

Regarding Your project: They can neither do USB-host/OTG nor HDMI.


Best Regards

[UKFlyer]

AFAIK no microcontroller has enough RAM onboard to hold a 640x480x24bit framebuffer so additional external RAM would be needed - i.e.not a single chip solution. I've coded a 640x480x3bit VGA output on a PIC32MZ (search for Micromite eXtreme) but this is absolutely at the limit of what is possible single chip. The code uses a particular facility of the PIC (framed SPI) that isn't available on STM so even harder on one of their chips.

As per the previous comments Raspberry-Pi Zero W is definitely the way to go. You will need an external A/D (MCP3424 or similar) as the Broadcom chips don't support analogue