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CHAPTER 14 16-BIT RELOAD TIMER (WITH EVENT COUNT FUNCTION)
14.1
Outline of 16-Bit Reload Timer (with Event Count Function)
The 16-bit reload timer consists of a 16-bit down-counter, a 16-bit reload register, one
input pin (TIN) and one output pin (TOT), and a control register. The input clock can be
selected from one external clock and three types of internal clock.
■ Outline of 16-bit Reload Timer (with Event Count Function)
The output pin (TOT) outputs a toggle output waveform in reload mode and outputs a square waveform
indicating counting in one-shot mode. The input pin (TIN) is used for event input in event count mode, and
can be used for trigger input or gate input in internal clock mode.
The MB90390 Series has two 16-bit reload timers.
■ Intelligent I/O Service (EI
The timer includes a circuit that supports EI
2
EI
OS can be used with both timers on this product. However, as both timers (ch.0 and ch.1) are connected
to the same interrupt control register (ICRx) in the interrupt controller, ch.0 and ch.1 cannot be assigned to
different EI
two different interrupt services. However, as ch.0 and ch.1 share an interrupt control register as described
above, the same interrupt level applies to both channels.
224
2
OS) Function and Interrupts
2
OS services. Also, as the two timers have different interrupt vectors, they can be assigned to
2
OS. The timer can activate EI
2
OS when an underflow occurs.
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