DESCRIPTION
The µPD4701A is a counter for an X, Y 2-axis incremental encoder. When a two-phase encoder  signal is input for the X and Y axes, direction discrimination and computation is performed, and count data is output in 8-bit parallel form. In addition, a 3-contact-point input buffer  is incorporated, which is useful for applications which use a pointing device such as a mouse or track-ball. The CPU checks the switch input flag or count flag and reads the 12-bit count data in two operations, one for the lower byte and one for the upper byte. The key input flag is output together with the count data in the upper byte.

FEATURES
• X, Y 2-axis incremental encoder counter
• Counter input (Schmitt-triggered input)
   X axis: XA, XB 2-phase signal
   4-multiplication count method used
   Y axis: YA, YB 2-phase signal
• Counters: 12-bit binary up/down counters (2 sets, X & Y) Reset value: 000H
• Count data output: 8-bit parallel latch output × 2 (including key input flag)
• On-chip 3-contact-point key input buffer circuit
• CMOS
• Single +5 V power supply