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Looking for Microcontroller to use

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joe_1

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Hi:

I have project which will require using some simple graphic stuff, and have menu. I looked at PICs and their best is 18F8720 which has 4k of RAM and 120K of ROM. I need more than that. So, I am looking for another microcontroller family which is also must be as popular but has higher RAM/ROM count, and not expensive. I also want it to have at least 60 I/O's.
If you have used any uController like that please let me know.

Thanks.
 
joe_1 said:
Hi:

I have project which will require using some simple graphic stuff, and have menu. I looked at PICs and their best is 18F8720 which has 4k of RAM and 120K of ROM. I need more than that. So, I am looking for another microcontroller family which is also must be as popular but has higher RAM/ROM count, and not expensive. I also want it to have at least 60 I/O's.
If you have used any uController like that please let me know.

It sounds more like you are heading towards micro-processors rather than micro-controllers - a system, rather than just a single chip.
 
What do you need more for? That's a crapload of code space. If you have a huge load of data (not instructions), you should probably consider an external EEPROM.

What's the project?
 
There are a bunch of ARM based controllers out there now. ARM is a 32bit architecture. Most of these controllers have an external bus so you can add memory - some even have an SDRAM controller built in. ATMEL, Philips, Sharp, OKI and a million others have ARM controllers. Other possiblilities are: SH from Renesas, M-core from Freescale, MIPS.
 
Oznog said:
What do you need more for? That's a crapload of code space. If you have a huge load of data (not instructions), you should probably consider an external EEPROM.

What's the project?

Well, I am trying to use graphic LCD in the project, and wanted to use window-like menu with it. I found places that sells software which incorporate these features along with the graphic LCD driver. Most of them require RAMs. I am still not sure which module I am going to use, but their required RAM usage range is 1k-6K. I am just concerned that taking big chunck of the little RAM that I have might leave little for the program data.
Microchip says the ROM can be expanded to 2M, but not the RAM. I am not even sure how much hassle it would be to expand the ROM, and use it in the code.

Joe,
 
Take a look at
**broken link removed**

A couple Dev Kits for Philips LPC ARM processor. the Controller has 16K of RAM and the boards are very cheap.
 
Most of the graphics stuff is just static bitmap data that will be stored on ROM. Otherwise you can use a simple I2C or SPI EEPROM for the graphics data.

128k is actually quite alot of data. Think of what we used to do on our Commodore 64's.

I don't know if you're just not thinking of it, or it's a design criteria, but you can use multiple uC's. Have one dedicated to the graphics processing, and others dedicated to your other I/O and processing tasks. Connect them up over the same I2C or SPI network.

Just try to use a uC that has hardware I2C or SPI to make it simpler.
 
About the I/O ports, why don't you use an i/o expansor
there are one which can handle 3 port of 8bit, the main port is multiplexed and then goes to the port A. B and C of the IC, I don't remember the number
 
joe_1 said:
Well, I am trying to use graphic LCD in the project, and wanted to use window-like menu with it. I found places that sells software which incorporate these features along with the graphic LCD driver. Most of them require RAMs. I am still not sure which module I am going to use, but their required RAM usage range is 1k-6K. I am just concerned that taking big chunck of the little RAM that I have might leave little for the program data.
Microchip says the ROM can be expanded to 2M, but not the RAM. I am not even sure how much hassle it would be to expand the ROM, and use it in the code.

Joe,

Something may be really wrong with their coding strategy to require that much RAM. Are you sure they actually mean RAM and not just code ROM space (which is rewritable, so it's sort of RAM by some defs)?

I'm confused as to what they're selling. They didn't design it for a specific target uC along with display that it works with? If it's portable C code, then they couldn't have the low level interface specified if they don't know the hardware and may not make very good use of PIC resourced.

If they actually require that much RAM and don't even know what processor they're coding for, I would find another way to do your project frankly.
 
They probably use a dual buffer setup with sprites and stuff. You can easily use that much ram once you start doing stuff lilke that.

The code is almost certainly not designed for an 8 bit processor - it sounds like 32 bit code.

I think you should start with something easier to get the hang of embedded systems. There are small black and white graphic displays that a PIC can control you might want to start with these and write your own driver code.
 
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