??? 03/06/09 00:22 Read: times |
#163131 - Be specific please. Responding to: ???'s previous message |
David Prentice said:
Richard,
Andy gave you a link to Luminary ARMs, NXP ARMs are similarly priced. You get 32k Flash + 8k RAM for £3 in single quantities or 128k Flash + 32k RAM for £5.35 So you get complete microcontrollers that require NO external support apart from xtals and 3V3 and 1V8 supplies. Apart from ranting about personal hygiene, surely you must be capable of doing a rough pound / dollar conversion. It is up to you which chips you choose to use, but why feign ignorance ? If you had really researched ARMs you would be aware of these facts. I also suspect that you know that Farnell is Newark in the US (I think). There will be more competitive prices out there. Andy just quoted a big-name distributor. David. Tell me something, David ... Why would I even consider for a moment buying anything from Newark? I was not aware of the link between Newark-U.S. and Farnell-U.K, but last time I ordered something from Newark, it was for standard delivery five days later, and costing $68.05 (an MC68HC705K EVK, which I ordered for a client in order provide it to that client on the following Saturday, meaning the Saturday of the week following the week after the Friday on which it was to be delivered. It was delivered on the Saturday on which I was supposed to deliver it to my client, hence was of no use at all, since I had to get one elsewhere in order to make the delivery, and, while they offered to refund my $68.05, they wouldn't refund the $273 that overnight delivery with Saturday a.m. delivery cost with that carrier. I might have let this slide, once, had it been the first time such a thing happened. Frankly, I'm not comfortable with European-manufactured ARM's because of that sad experience I had with ATMEL's ARM products. They have, I'm sure, fired those French designers, but they've probably gone to work for someone else, doing the same sort of things. My ARM experience has been primarily with SAMSUNG ARM CPU's, though that's several years old. I do read the trade rags and spam relating to MCU's, and don't believe any of the ones possibly in the right price range offer the performance of which I previously wrote. The exchange rate pounds to dollars makes the £3 cost $4.28. I was thinking about an earlier exchange rate, closer to $1.97 from a month ago or so, but I'd be really interested to know how this relatively thrifty ARM performs relative to that $6 Maxim/Dallas part, particularly in the context of that data transfer task. Now, performance is of considerable import, so tell me, does that $4.28 ARM allow you to move 256 bytes on an odd-byte boundary and in bytes in less than 65 microseconds, say, from RAM to external 8-bit port? Quite frankly, I haven't thoroughly researched ARM-core microcontrollers because I'm not in need of them right now. When the need arises, I'll probably do a through trade study. In the meantime, however, I'll wait for something to jump out at me. I have nothing against ARM, but I have no reason to run a trade study until I have an application for a new MCU. Every time someone comes along wanting to program a microcontroller in 'C', I tell 'em to use an ARM. I've amply explained why I don't want to do that myself ... yet. RE |