FT629 Datasheet, PDF (1/2 Pages) List of Unclassifed Manufacturers – Switch Detection Chip

FT629 ‘Otter’
Switch Detection Chip
General Description:
The FT629 is a switch detection chip. It will
detect a change on any of its five input pins and
send one byte out of the TX pin. The output
byte’s lower five bits correspond to the state of
the input pins 1-5.
Figure 1: FT629 pin out
Operation:
The operation of the FT629 is very simple. It
will transmit one byte each time there is a
change on one of its input pins.
There is some debouncing built into the FT629.
It will detect a change on the input pins and then
send out one byte. Therefore, there will be a
4.16 ms delay after a change is detected before it
will check for another pin change.
Although the FT629 was designed to read switch
inputs, it has other possible uses such as
detecting the outputs from comparators and logic
circuits.
Applications:
The FT629 was designed specifically to aid in
the making of a robot using a portable electronic
device that has a serial port (e.g., HP48, Palm
Pilot, BASIC Stamp, etc.).
Description of Output:
A single byte is output by the FT629 whenever
the status of one of its input pins has changed.
The status of each pin is encoded into the lower
five bits of the output byte, according to Figure
2.
Figure 2: Output Byte Organization
X X X Pin5 Pin4 Pin3 Pin2 Pin1
Bit7 Bit6 Bit5 Bit4 Bit3 Bit4 Bit5 Bit6
X:
does not matter
Pin[1-5]: 0 = switch open
1 = switch closed
© 2001 FerretTronics, Inc.
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