Microcontroller choice

[raivo]

I need microcontroller with integrated AD & DA converter serial & parallel IO and external bus with some kind of DMA capability. Address space must be at least 4 megs. And this chip must be available in socketable package (like PLCC or PGA). Any suggestions? I know, Toshiba makes such micros but thoose are not very easyli available - especially in small quantityes. Any other ideas?

 

[cbarn24050]

hi, what exactly do you mean by DMA? ie from what to what. Some micros let youput them in hold mode and use the bus as you want I know of none that let you have direct access to on chip periferal registers. Do you really need socketed parts? quite a few can be reprogrammed in situ.How fast do you need? how many bits on the a/d, d/a?

 

[raivo]

At first i want do know is there some parts at all near to theese specifications As you know yourself i can use external AD & DA as well and to use also external DMA controller. But i'd like to get it all in one chip. Its enough of 8 bit AD ( 10 bit is ideal).

Problem is to build some environment monitor like all those temperature - humidity - pressure logers but this must also store some low-res images from CCD. As max rate for image storage ever needed may be 1 frame in 60 sec (probabaly a lot less) then this is not speed critical. Image resolution will be something like 200x300 8bit pixels.

I know Toshiba makes micros that have even internal DRAM controller and true DMA controller. But i probably can't got hand on theese. So i want any ideas for easily available chip that will someway do the job.

 

[47gandalf]

You have not yet given enough information to make a clear choice of processor. For example, in the ADC and DAC circuits, how many bits of precision do you need? How many bits of accuracy? How many samples per second must each handle?

Processor programming language? Estimated program size when complete? Clock speed (internal and bus)? Power restrictions? Hardware subsystem needs (divider, multiplier, PWM)?

And a number of others. Start with as much as you can tell us about what you want to do, without telling any secrets.

Any mechanical, environmental, electrical, temperature range or other constraints? Budgetary price for the whole design? One of a kind test box or production product? At what estimated annual rate? All these things have a bearing on what is a good solution to your problem.

And about the issue of sockets, many packages that are meant to be surface mounted can be put in a special socket for debugging while you make the prototype, then soldered down to the PCB after the product design is finished. I'm doing a design right now with one processor in 28-pin SOIC and one in 112-pin TSSOP. The prototype boards have (expensive) ZIF sockets that allow me to change processors easily. The final PCBs have surface mount footprints for the processors.

And both processor can be programmed (or re-programmed if necessary) right on the board. Flash program memory with low voltage programming capability. That lets us change code to the latest just before we send product out the door. So the very latest changes, improvements (and fixes) are always what we ship.

 

[biomedicalEng]

Hi
National Semiconductor has a very powerfull Microcontroller with A/D, D/A, PWM, CTCs, SPI, UART and ... peripherals (Sorry i forgot it's number!).

you can also use ATmega Microcontrollers of Atmel corporation.

and at last take a look at Microchip, they have very nice and high efficient MCUs.