| ??? 07/10/03 01:01 Read: times |
#50379 - RE: Short Timing delays Responding to: ???'s previous message |
Raghu:
Followup on previous message: If a Dallas processor (or similar) is NOT available, probably the most effective method is to simply slow down the processor clock for that read cycle. If you have an external oscillator, as opposed to just a crystal, you could run it through a flop or two to divide it by two or four, with a selector gate made up of NAND or other gates controlling which clock the CPU sees. The gates could be controlled by one I/O pin on the processor. You would set the clock slow, perform the read, then speed it up again for the rest of the program. As I said above, adding external logic, with it's attendant prop delays, could mean that the RD pulse will have gone high internally, and therfore latched the data bus contents, long before the data is valid. |



