MB90480/485 Series
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.
Count modes
Timer mode
Up/down count mode
Phase differential down count mode ( × 2)
Phase differential down count mode ( × 8)
• In timer mode, there is a choice of two internal count clock signals.
Count clock
125 ns (8 MHz : × 2)
(at 16 MHz operation)
0.5 µs (2 MHz : × 8)
• In up/down count mode, there is a choice of trigger edge detection for the input signal from external pins.
Edge detection
Falling edge detection
Rising edge detection
Both rising/falling edge detection
Edge detection disabled
• 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.
ZIN pin
Counter clear function
Gate 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.
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
• 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.
46
FUJITSU [ FUJITSU ]
