
MB90480B/485B Series
46
6.
8/16-bit up/down Counter/Timer
8/16-bit up/down counter/timer consists of up/down counter/timer circuits including six event input pins, two
8-bit up/down counters, two 8-bit reload/compare registers, as well as the related control circuits.
(1) Principal Functions
8-bit count register enables counting in the range 0 to 256.
(In 16-bit
× 1 mode, counting is enabled in the range 0 to 65535)
Count clock selection provides four count modes.
In timer mode, there is a choice of two internal count clock signals.
In up/down count mode, there is a choice of trigger edge detection for the input signal from external pins.
In phase differential count mode, to handle encoder counting for motors, the encoder A-phase, B-phase, and
Z-phase are each input, enabling easy and highly accurate counting of angle of rotation, speed of rotation, etc.
The ZIN pin provides a selection of two functions.
A compare function and reload function are provided, each for use separately or in combination. Both functions
can be activated together for up/down counting in any desired bandwidth.
Individual control over interrupts at compare, reload (underflow) and overflow events.
Count direction flag enables identification of the last previous count direction.
Interrupt generated when count direction changes.
Count modes
Timer mode
Up/down count mode
Phase differential down count mode (
× 2)
Phase differential down count mode (
× 8)
Count clock
125 ns (8 MHz :
× 2)
(at 16 MHz operation)
0.5
s (2 MHz : × 8)
Edge detection
Falling edge detection
Rising edge detection
Both rising/falling edge detection
Edge detection disabled
ZIN pin
Counter clear function
Gate functions
Compare/reload function
Compare function (output interrupt at compare events)
Compare function (output interrupt and clear counter at compare
events)
Reload function (output interrupt and reload at underflow events)
Compare/reload function
(output interrupt and clear counter at compare events, output interrupt
and reload at underflow events)
Compare/reload disabled