| ??? 02/05/07 19:15 Read: times |
#132076 - yes I have Responding to: ???'s previous message |
but you can get nearly a 10x performance increas with EPP (NOT ECP!!!) I don't care how fast the data is being sent to the circuit from the computer. If I have to wait 10 ms per byte, I will. Have you tried any of this at all? I tried the parallel port before and it works with me. See my other recent posts. You do have an oscilloscope and a logic analyzer, don't you? No, and if I needed a logic analyzer, I would make an LED and resistor in series and apply it to test points. The EPP hardware is REALLY difficult. I don't need it. I will use SPP, and it is fast enough for me. I'm not expecting a ridiculously fast system. ...(define that in terms of allowable minima and maxima) which I gather is what you intend to do. I am synchronizing the circuit with the parallel port. The parallel port will send a signal when it is ready with the next piece of data. If I had it asynchronous (where the clock constantly ran), then 1/2 the data wouldn't be fed in because the microprocessor won't give enough time to the parallel port. When I do it my way, I have it where the whole microprocessor halts (clock frozen) until the port issues a signal. I'd suggest that you ensure that you understand all the inherent timing requirements before attempting this, That is why I am going synchronous. How do you know that it works? Have you examined it with oscilloscope and logic analyzer? I have made a basic 8051 system before, and it worked. It had 74HCT series chips with it too. The problem with it was that the eeprom had to be taken out everytime I wanted to program it. are you sure it applies to the EEPROM? Doesn't it have some page-boundary considerations you have to take into account? Doing it my way would require about 10ms waiting time. This means I can write 1 byte at a time. Also, I have done it before too. If I connected the address lines in order, then I can write 32 bytes at a time within about 100 microseconds. I think. Have you considered that there's a minimum speed at which you can operate this part? You did say you're using the Intel HMOS part, didn't you? If you use a later, CMOS, part you won't have this concern. I'm using CMOS. Intel's 80C51BH. I think you'll find that this approach is much slower than than what you need. Speed is not an issue at this point. How much rate-experimentation have you done with the SPP? I've used it some, and have found it quite "challenging" to attain 50 kBytes per second. I don't even need 50 KB/s Maybe 1 KB/s. |
