(no subject)
For our design project, I had a problem where, when addressing my LCD module, the LED bar seemed to be displaying whatever bit pattern I was sending to the LCD, suggesting that the LED port was enabled, despite the fact that I wasn't addressing it in code. I hooked the board up to the logic analyzer and saw that that was true. The issue was that the address on the address bus wasn't ready until about 250ns after the processor activated the signal indicating an I/O operation. The address bus held zero at the time the I/O signal went active , and my LEDs were located at address 0h--evidently 250ns was long enough for the port to latch the contents of the data bus. So, I had to move the LEDs to a higher address and then it worked fine.
Talk about fine timing, now let's try a Ghz core rather than a 5Mhz 8086 ...
Talk about fine timing, now let's try a Ghz core rather than a 5Mhz 8086 ...