DESCRIPTION OF OPERATIONS
1. COUNT OPERATION
The µPD4701A executes an up-count and down-count by means of A & B 2-phase signals in the 12-bit up-down
counter. An up-count is performed when the A-phase signals (XA, YA) are phase-advanced, and a down-count is
performed when the B-phase signals (XB, YB) are phase-advanced. The edge of each signal is a count source. (4-
multiplication count method: see Fig. 1.)
Fig. 1 Count Operation Timing Chart
(X, Y)A Input
(X, Y)B Input
This count operation is executed independently for the X axis (XA, XB) and Y axis (YA, YB). This operation is
initialized by reset input (RESET X, RESET Y) only.
In an up-count, the next value after FFFH is 000H, and in a down-count, the next value after 000H is FFFH.
2. OPERATION OF COUNT FLAG, CF
The count flag, CF, indicates that a count source (either XA, B or YA, B edge input) has occurred while the CS signal
is “H”, and is an active-low output. CF is reset (→ “H”) by CS signal “L” input. While CS = “L”, count flag output is
disabled and the “H” level is output.
Fig. 2 Count Flag Output Timing Chart
Count Flag Output Disabled in these Periods