MB90470 Series
45
6.
8/16-bit Up-down Counter/Timer
This block is an up-down counter/timer configured with six event input pins, two 8-bit up/down counters, two
8-bit reload/compare registers, and related control circuits.
(1) Principal functions
8-bit count registers for counting in the range 0 to 256.
(Also operates in 16-bit
× 1 mode for counting in the range 0 to 65535.)
Count clock selection provides four count modes.
In timer mode, there is a choice of two internal count clocks.
In up/down count mode, there is a choice of external pin input signal detection edge.
In phase differential count mode, to provide counts for encoders for motors, etc., the A phase, B phase, and
Z phase of the encoder can be input separately for highly precise counts of rotation angle, rotary speed, etc.
The ZIN pin provides a choice of two functions.
Compare and reload functions are provided, each available independently or in combination. Both can be
started together to provide any desired type of up/down count.
Individually controllable interrupts at compare, reload (underflow) and overflow events.
Count direction flag enables detection of immediately preceding count direction.
Interrupt generation at change of count direction.
Count mode
Time mode
Up/down count mode
Phase differential count mode (2
× )
Phase differential count mode (8
× )
Count clock
125 ns (8 MHz : divided by 2)
(16 MHz operation)
0.5
s (2 MHz : divided by 8)
Detection edge
Falling edge detection
Rising edge detection
Falling/rising edge, both edges’ detection
Edge detection disabled
ZIN pin
Counter clear function
Gate function
Compare/reload function
Compare function (outputs interrupt at compare events)
Compare function (outputs interrupt and clears count at compare events)
Reload function (outputs interrupt and reloads at underflow events)
Compare/reload function
(outputs interrupt and clears count at compare events, outputs interrupt
and reloads at underflow events)
Compare/reload disabled