| ??? 02/15/05 19:29 Read: times |
#87570 - Strobe valid? Responding to: ???'s previous message |
Hello Ro,
Should you have strobe going into INT0 (interrupt zero) and INT0 is setup to be edge triggered then you should see valid data when a DTMF signal has been detected by the MT8870D DTMF receiver. You should be able to troubleshoot this with a simple volt ohm meter to determine if the DTMF receiver is working. With respect to the below block diagram (http://assets.zarlink.com/FD/mt8870d_block.jpg) describe how you have the other pins hooked up. Regards, Charles Bannister Pin 15(DIP IC) StD Delayed Steering (Output). Presents a logic high when a received tone-pair has been registered and the output latch updated; returns to logic low when the voltage on St/GT falls below VTSt. Pin 16 (DIP IC) ESt Early Steering (Output). Presents a logic high once the digital algorithm has detected a valid tone pair (signal condition). Any momentary loss of signal condition will cause ESt to return to a logic low. MT8870D DTMF RECEIVER BLOCK DIAGRAM 
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| Topic | Author | Date |
| 4 bit binary input | 01/01/70 00:00 | |
| Swap and Mask | 01/01/70 00:00 | |
| as I read your post | 01/01/70 00:00 | |
| FAO Eric the Great. | 01/01/70 00:00 | |
| oops | 01/01/70 00:00 | |
| Updated profile | 01/01/70 00:00 | |
| It is useful! | 01/01/70 00:00 | |
| already shown | 01/01/70 00:00 | |
| Reformatted Code for readability | 01/01/70 00:00 | |
| Neat | 01/01/70 00:00 | |
| re:neat | 01/01/70 00:00 | |
| risque business | 01/01/70 00:00 | |
| Strobe | 01/01/70 00:00 | |
| Strobe valid? | 01/01/70 00:00 | |
For any pinout | 01/01/70 00:00 |