Data port selection

Details Data port selection Data port selection

1987-12-09

1990-04-24

Harkcom, Gary V.

Boots, shoes, and leggings

36492792, 36492795, G06F 1300

Patent

active

049205110

ABSTRACT:
In order, for example, to expand the input and output of a microcomputer (7) having a serial input/output capability, a parallel data input port (2 or 3) or output port (4 or 5) is selected by clocking serial selection bits from a serial data line (1) into a first shift register (56) and then enabling a latch (58) for the register parallel output (57). This results in a change in level on a particular one of a set of a parallel output lines (35,36,49,50) which corresponds to the particular group of selection bits written, and hence to a particular port. If the selected port is an output port the change in level results in the strobing of a latch (43 or 44) corresponding to that port, and hence the transfer of the contents of a further shift register (39 or 40) corresponding to that port. These contents are previously written in from the serial data path (1), each further shift register (39,40) being connected in cascade with the first register. If the selected port is an input port the change in level results in the enabling of a gate (31 or 32) corresponding to that port, and hence to the transfer of the port information to a shift register (27 or 28) corresponding to that port, whence it is subsequently clocked out to the serial data path via a respective transistor (25 or 26).

REFERENCES:
patent: 4174536 (1979-11-01), Misunas et al.
patent: 4689740 (1987-08-01), Moelands et al.

Affiliated with

Also associated with

Rating

Data port selection does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Data port selection, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Data port selection will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-39040