HD6433713 datasheet(158/324 Pages) RENESAS

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Auto-reload timer operation

Setting bit TMB7 in TMB to 1 causes timer B to function as an 8-bit auto-reload timer.

When a reload value is set in TLB, the same value is loaded into TCB, becoming the value

from which TCB starts its count.

After the count value in TCB reaches H'FF, the next clock signal input causes timer B to

overflow. The TLB value is then loaded into TCB, and the count continues from that value.

The overflow period can be set within a range from 1 to 256 input clocks, depending on the

TLB value.

The clock sources and interrupts in auto-reload mode are the same as for interval mode.

In auto-reload mode (bit TMB7 = 1), setting a new TLB value also initializes TCB.

Operation on external clock

Timer B can operate on an external clock input as an event signal at pin P10/IRQ0. External

clock operation is selected by setting bits TMB2 to TMB0 in timer mode register B to all 1’s

(111). TCB can count either rising or falling edges of the input at pin P10/IRQ0.

When timer B is used to count external event input, bit IRQC0 in port mode register 1

(PMR1) should be set to 1, and bit IEN0 in interrupt enable register 1 (IENR1) should be

cleared to 0 to disable IRQ0 interrupt requests.

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HD6433713 Datasheet(PDF) 158 Page - Renesas Technology Corp