Ken Shirriff writes, “A die photo of a vintage 64-bit TTL RAM chip came up on Twitter recently, but the more I examined the photo the more puzzled I became. The chip didn’t look at all like a RAM chip or even a TTL chip, and in fact appeared partially analog. By studying the chip’s […]
Tag Archives: DTMF
DTMF decoder test circuit
Kenneth Finnegan writes: As part of a few projects I’m working on, I want circuits to be able to decode DTMF tones played over an amateur radio link for remote control. This can be done with a moderately powerful processor in DSP, but I opted to buy a handful of MT8870D dedicated DTMF decoder chips […]
Propeller DTMF generator object
If you need to generate DTMF tones and have a Parallax Propeller chip handy, there’s an object for that! Thomas E. McInnes has coded up this DTMF generator object for the Propeller. Written in Spin, the object includes functions for dialing individual digits or a preprogrammed phone number, along with the required Synth object as […]