32 bit microcontroller with external memory bus needed

Apr 14, 2010 6 Replies
W

I'm looking to branch out beyond the PIC chips that I've programmed in the past. I'm looking for a 32 bit microcontroller with an external memory bus.



Beyond those requirements, speed is probably the next concern. I'd prefer something with16 bit ADC and DAC but I suppose that might be asking a bit much. Of course, it has to cost nothing...



Seriously, I'm quite unfamiliar with the 32 bit microcontroller world and trying to find a part with an external memory bus hasn't been as easy as I thought it would be. It can be downright impossible to determine from a mfr's literature which parts have the external bus interface and which don't.



So I thought I'd come to the group for recommendations. I am a hobbyist, and while I'm willing to spend some money on development boards and tools, I'm not going to spend past 'this-is-fun' levels.



I appreciate your input!


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A

Atmel has a few 32-bit MCUs with external memory busses. Note that the number of pins required for this functionality is quite high, so you end up with quite large TQFP packages or BGA packages. If it is for extra memory, then some have busses that can interface directly to DDR RAM. If it is for external peripherals, then using 8 or 16 bit external busses are often fast enough.

Regards Anton Erasmus

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O

Lots of coldfire derivatives, the cheapest with external bus is likely the Kirin 3 (MCF52259).

Runs at 80MHz, the internal Flash (512KiB) runs nearly without wait states (2-1-1-1 IIRC), 64KiB internal RAM without wait states.

There are much faster derivatives.

I would be surprised if such a uC existed.

Oliver

Oliver Betz, Munich despammed.com might be broken, use Reply-To:
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M

STM32F ARM range

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zillions of variants including some with external memory interface but ony 12 bit ADC. Very cheap development tool ST-LINK for about £17 - includes software. There are real tools too because its an ARM.

Also Atmel Xmega (not 32 bit) - some have external DRAM interface which is rare on an 8 bitter. There is a cheap dev board Xplain for about £30 and I think that includes a debug tool via USB.

Michael Kellett

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D

At about 3 times the cost ($36 single at Digikey, used to be $24...) the MPC5200B is hard to beat on power/price. Of course no ADC, but plenty of SPI, codec etc. intertfaces.

Dimiter

------------------------------------------------------ Dimiter Popoff Transgalactic Instruments

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-

Do you mean external CODE memory, (how much?) or a parallel bus that can interface to SRAM like peripherals ?

You are unlikely to get both External memory and 16b analog. eg ADi have ARM variants with 16/24b ADC, but they are microcontrollers. (ie on chip code only) I see their newest Eval boards are getting cheaper.

=3Djg

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M

Some of the NXP LPC2xxx ARM7 devices (e.g. LPC2478) have external memory bus, with SRAM and SDRAM controller

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