| ??? 02/06/07 22:09 Read: times |
#132182 - What's his primary purpose Responding to: ???'s previous message |
Sasha Jevtic said:
Richard Erlacher said:
They have download-programing via the serial port. Theirs run at 33 MHz, and they are one-clockers. They'll even send you a free sample if you request one.
RE Although I have used the DS89C4x0 devices with good results, they're a bit quirky, and probably not the best choice for someone just getting started and/or without a solid bench setup (e.g., scope/logic analyzer). They are prone to ALE noise, and especially when operated at 33 MHz, can readily generate interface timings that are not HC logic-friendly. --Sasha Jevtic I don't doubt your opinion for a moment. Their bus timing is odd, and their serial channel spec's are incomplete. I'm not at all sure about their interrupt response times, either. However, I don't think mike's problems are well-enough defined. I'm not sure whether he wants to spend the next year learning about how to use MCU's or the next 5 years learning about how to create PCB's in his kitchen. I also don't know whether he wants to program EEPROMs or whether he wants to build MCU applications. Not only that, I don't know how he wants to apply his PC. Is it to be the controller for the EEPROM programmer? Is it to be the terminal for his MCU board? Is it to be the human interface for his "ultimate widget" about which he's said nothing? Where do you suppose he wants to "go" with this? It's pretty certain that he doesn't know enough about how to make the circuit he's described so far work. He's apparently unaware that there are two ALE/nPSEN activations for every external program memory access, but only one for every XRAM access. Apparently he's learned to swim, somewhat, but now he's trying to swim the English Channel. I wish him luck! RE |
