| ??? 05/28/09 07:26 Read: times |
#165657 - Do you really need 3? Responding to: ???'s previous message |
Batu C. said:
AT89S52 has just two external interrupt pins (INT0 and INT1-both active-LOW). But I have three interrupt sources on my design. First one is PCF8583-clock/calender chip, second one is ADE7753 Energy Meter chip and the last one is push-buttons which have been tied eachother with a wired-OR connection Firstly, Do you really need interrupts from all 3 sources? Could you just poll either or both of the chips? Can you connect the PCF8583 and ADE7753 together to, say, INT0, and the buttons to INT1? Then, when an INT0 occurrs, you poll the 2 chips to find out which one interrupted... I thought: if I combine all these three interrupt signals by a wired-OR ... But, I could not be sure whether I'll be able to capture the source or not. All the ISR would need to do is to read the 3 pins, and save that in some variable - it should be fairly easy to work out the maximum time that could take and, thus, whether you can be sure of capturing the source. If you can't be sure internally, you'll have to add some external registers... |
| Topic | Author | Date |
| Multiple Interrupt Sources | 01/01/70 00:00 | |
| Do you really need 3? | 01/01/70 00:00 | |
| I need 3 different Int. Sources | 01/01/70 00:00 | |
| Timer 2 capture mode | 01/01/70 00:00 | |
| I can suggest 2 methods | 01/01/70 00:00 | |
| Thanks For T2 | 01/01/70 00:00 | |
T2 | 01/01/70 00:00 |