| ??? 01/02/03 14:29 Read: times |
#35411 - RE: P89C557E4 |
while (1} { P1 = 0 p1 = 1 } This is what i have. run it and put a scope on a p1 pin. P1 is always HIGH (= +5V) EA is connected to /PSEN by a 3k3 resistor, and seems to be +5V EW is +5V (active low, thus disabled) It Is NOT EA it is !EA, and thus it must be low to enable external program fetch. external program should be disabled. PSEN is +5V EA is a square wave EA is connected to PSEN via a 3k3 resistor, this is how i got the hardware. !PSEN should pulse if the chip is running, put a scope on. I did do that, and it displays a square wave |
| Topic | Author | Date |
| P89C557E4 | 01/01/70 00:00 | |
| RE: P89C557E4 | 01/01/70 00:00 | |
| RE: P89C557E4 | 01/01/70 00:00 | |
| RE: P89C557E4 | 01/01/70 00:00 | |
| RE: P89C557E4 | 01/01/70 00:00 | |
| RE: P89C557E4 | 01/01/70 00:00 | |
| RE: P89C557E4 | 01/01/70 00:00 | |
| RE: P89C557E4 | 01/01/70 00:00 | |
| RE: P89C557E4 | 01/01/70 00:00 | |
| RE: P89C557E4 | 01/01/70 00:00 | |
| RE: P89C557E4 | 01/01/70 00:00 | |
| RE: P89C557E4 | 01/01/70 00:00 | |
| RE: P89C557E4 | 01/01/70 00:00 | |
| RE: P89C557E4 | 01/01/70 00:00 | |
RE: P89C557E4 | 01/01/70 00:00 |



