| ??? 03/31/09 06:15 Read: times Msg Score: +1 +1 Informative |
#164035 - Pulling to 0 |
Hi all,
I have a problem reading the pin 9 of a 74HCT165 from the port P2. Let me explain what I did: - Pin 9 (Q7 output) of the 74HCT165 is connected to P2.0. - Before doing anything I set P2.0 to 1 to make it usable as an input. It looks like the 74HCT165 is not able to pull down the P2.0 to the level 0: - If I disconnect the 74HCT165 and set P2.0 to level 0 using a wire then I can read 0, that's normal. - Always disconnected if I correctly drive the 74HCT165 I can see the Q7 output reaching the level 0 when it should (using a multimeter). - As soon as both of them are inter-connected no way to get P2.0 at the level 0! Whether I test P2.0 == 0 or P2.0 == 1 both of the comparisons are true! Thank you to help me clarify my mind. Michel |
| Topic | Author | Date |
| Pulling to 0 | 01/01/70 00:00 | |
| chips | 01/01/70 00:00 | |
| 89C450 | 01/01/70 00:00 | |
| Set a pin as input | 01/01/70 00:00 | |
| Port pin as an input | 01/01/70 00:00 | |
| Put load on HCT output | 01/01/70 00:00 | |
| Checking | 01/01/70 00:00 | |
| I see what you want to do there ... but ... | 01/01/70 00:00 | |
| so check 74hc165 with resistive load only | 01/01/70 00:00 | |
| It's not uncommon... | 01/01/70 00:00 | |
| I know that some use antiques, but ... | 01/01/70 00:00 | |
| Do we mean the same? | 01/01/70 00:00 | |
| I asid 'modern', not Arghmel | 01/01/70 00:00 | |
| Come on, Erik.... | 01/01/70 00:00 | |
| now let me get this straight ... | 01/01/70 00:00 | |
| one thing I always do ... | 01/01/70 00:00 | |
| Shame on me! | 01/01/70 00:00 | |
| Oops! | 01/01/70 00:00 | |
| Been there, done that | 01/01/70 00:00 | |
IO expansion | 01/01/70 00:00 |