External bus interface? What device(s)?

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#1
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I need external bus interface for adding peripherals the AVR do'nt have.

But I find it difficult to find in parametric searches at Farnell and others. And the Devices section in AVRFreaks seems to be abandoned. :cry: And send me on to a place where I can only do ASCII searches (back to the eighties).

Does ayone know where I can set up my wish list and get out the possible devices? That would probably be more productive than just giving me the answer to the question on the subject line.

And yes, I noticed the Parametric Table in Excel, but according to it only the AVR UC3 can have external bus. And using the "stoneage search method" I at least found that XMega64A1 have it.

Einar Sjaavik

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All the A1 Xmegas have it. But exactly what do you mean by "external bus interface" anyway. The mega64, mega128, mega162, mega640, mega1280, mega1281, mega256, mega2561 all have the capability to support 64K of External Memory (more if you bank it). There may be others though it will tend to be the high pin count devices as so many pins are involved in Data and Address buses (though they are multiplexed)

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Thanks!

I mean I need to access a peripheral. In this case 2 Dual Port RAM's (2-8K). But I hit a similar problem a while back where it was just one 2K DPR. Motorola 6809 style access preferred, but demuxing is usually easy if that's what is needed. Cheap parts anyway.

Did you take that off the top of your brain, or do you have a Secret AVR Search Tool?

Einar Sjaavik

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Quote:

Did you take that off the top of your brain,

Rather sadly yes - but for that reason the list is almost certainly not definitive - others may remember other Mega's with External Memory. Actually I just had a thought, those that do will have the control registers necessary...

C:\WinAVR-20100110\avr\include\avr>grep XM *.h

iocanxx.h:#define XMCRA _SFR_MEM8(0x74)
iocanxx.h:#define XMCRB _SFR_MEM8(0x75)
iocanxx.h:/* Register Bits [XMCRB]  */
iocanxx.h:/* External Memory Control Register B - XMCRB */
iocanxx.h:#define    XMBK         7
iocanxx.h:#define    XMM2         2
iocanxx.h:#define    XMM1         1
iocanxx.h:#define    XMM0         0
iocanxx.h:/* Register Bits [XMCRA]  */
iocanxx.h:/* External Memory Control Register A - XMCRA */
iom128.h:#define XMCRB     _SFR_MEM8(0x6C)
iom128.h:#define XMCRA     _SFR_MEM8(0x6D)
iom128.h:/* External Memory Control Register A - XMCRA */
iom128.h:/* External Memory Control Register B - XMCRA */
iom128.h:#define    XMBK         7
iom128.h:#define    XMM2         2
iom128.h:#define    XMM1         1
iom128.h:#define    XMM0         0
iom162.h:#define XMBK   6
iom162.h:#define XMM2   5
iom162.h:#define XMM1   4
iom162.h:#define XMM0   3
iom32u4.h:#define TC4H _SFR_MEM8(0xBF)    /* Per XML device file. */
iom32u6.h:#define XMCRA _SFR_MEM8(0x74)
iom32u6.h:#define XMCRB _SFR_MEM8(0x75)
iom32u6.h:#define XMM0 0
iom32u6.h:#define XMM1 1
iom32u6.h:#define XMM2 2
iom32u6.h:#define XMBK 7
iom64.h:#define XMCRB     _SFR_MEM8(0x6C)
iom64.h:#define XMCRA     _SFR_MEM8(0x6D)
iom64.h:/* External Memory Control Register A - XMCRA */
iom64.h:/* External Memory Control Register B - XMCRA */
iom64.h:#define    XMBK         7
iom64.h:#define    XMM2         2
iom64.h:#define    XMM1         1
iom64.h:#define    XMM0         0
iom8515.h:#define    XMBK         6
iom8515.h:#define    XMM2         5
iom8515.h:#define    XMM1         4
iom8515.h:#define    XMM0         3
iomxx0_1.h:#define XMCRA   _SFR_MEM8(0x74)
iomxx0_1.h:#define XMCRB   _SFR_MEM8(0x75)
iomxx0_1.h:#define XMBK    7
iomxx0_1.h:#define XMM2    2
iomxx0_1.h:#define XMM1    1
iomxx0_1.h:#define XMM0    0
iousbxx6_7.h:#define XMCRA   _SFR_MEM8(0x74)
iousbxx6_7.h:#define XMCRB   _SFR_MEM8(0x75)
iousbxx6_7.h:#define XMBK    7
iousbxx6_7.h:#define XMM2    2
iousbxx6_7.h:#define XMM1    1
iousbxx6_7.h:#define XMM0    0

So I forgot the mega8515 and some of the USB and CAN devices.

Cliff