I am trying to use the MT8880C DTMF transceiver in a ham radio repeater controller, using the 9S12C128 chip, and programming it with gcc.
I have it working fine for output setting it up by the instructions in the data sheet. As part of a POST, I send all the DTMF digits in non-burst mode OK.
Again, following the guide in the data sheet, when I add the code to read the data register when I get an IRQ from valid DTMF, it subsequently starts sending constant tone even though I don;t tell it to, and forever hold the IRQ line down LO.@
I am hoping someone has been there before and can shine some light on the problem!
thanks for any help,