Interfacing PIC to removable memory

qoou · Joined: 28 Sep 2016 Posts: 14

I'm using a PIC16F1789.

I'd like to have some type of removal memory storage interfaced with the pic. The type of memory device is not important, as long as I can easily remove it and connect it to a computer.

The memory device will contain only a small file (.txt) with configuration data. This data will be read during startup by the pic. I will not write any data to the memory device after connecting to the pic.

I've never done something like this before, and would just like a bit of advice before I possibly get in over my head. The types I've primarily looked at are MicroSD or a USB flash drive. However, the general impression I've gotten is that I'll need a different chip to handle these (PIC18+). I've also looked at interface chips such as FT230XS-R, to bridge USB to UART to help interface to the PIC; however it's not immediately obvious to me how this is accomplished.

I've seen that CCS has some built-ins for these types of interfaces, but not sure which type is most feasible or preferred.

Is something like this feasible?
Would a different PIC be required/suggested?
What type of memory is easiest to interface to?

Appreciate any feedback.

Ttelmah · Joined: 11 Mar 2010 Posts: 19552

For direct connection, SD far easier. But you need a PIC with lots of RAM, and preferably 3.3v to do this. To handle a USB stick, you would need to implement a USB master.....

However much easier solution. Use a FTDI Vinculum. This is a tiny chip/board (available as a bare chip or as a pre-built board/module). Do a search for 'VDRIVE3'. This does all the work for you. Handles USB, opening files etc., just needs a serial connection to the PIC. Simple ASCII commands to open a file, write things to it etc..

temtronic · Posted: Wed Jun 14, 2017 10:44 am

I have to 'second' Mr. T's choice of the Viniculum devices. Super easy to get 'up and running', easier than an SD device...though more $$ up front. IF you value your time, it is the way to go.
One hint... If you store your data in 'Comma Separated Variable (CSV) format (x,y,z,a,..cr/lf, check online for format...). A PC with Excel can 'autoload' the data into a spreadsheet ! THAT makes it quick and easy to confirm the data is good, saving you days of frustration wondering why the VB program you cut isn't working......

Jay

benoitstjean · Posted: Sat Jun 17, 2017 6:42 am

Or get yourself a PIC24EP512 which has a load of program space and lots of RAM and get your hands on Brush Electronics' SD card driver. It works flawlessly, can be used royalty-free and is not super expensive, around 150$ USD.

Depending on if this is a personal project (therefore 150$ might be overboard), you could always use the SD card over SPI as a straight raw device but you need to understand the concept of SD cards and why data must be written in blocks, reading and writing to the same spot will wear-out the card prematurely etc.

There is a lot of science behind SD technology, it's not like reading and writing to a standard EEPROM starting at address 0.

Good luck.

Ben

benoitstjean · Posted: Sat Jun 17, 2017 7:06 am

Or get yourself a PIC24EP512 which has a load of program space and lots of RAM and get your hands on Brush Electronics' SD card driver. It works flawlessly, can be used royalty-free and is not super expensive, around 150$ USD.

Depending on if this is a personal project (therefore 150$ might be overboard), you could always use the SD card over SPI as a straight raw device but you need to understand the concept of SD cards and why data must be written in blocks, reading and writing to the same spot will wear-out the card prematurely etc.

There is a lot of science behind SD technology, it's not like reading and writing to a standard EEPROM starting at address 0.

Good luck.

Ben