Datasheet

Section 14 Timer RB
REJ09B0465-0300 Rev. 3.00 Page 419 of 982
Sep 17, 2010
H8S/20103, H8S/20203, H8S/20223, H8S/20115, H8S/20215, H8S/20235 Group
Section 14 Timer RB
The timer RB is an 8-bit reload timer with an 8-bit prescaler. The prescaler and the timer are each
comprised of a reload register and a counter. The timer RB has two reload registers: timer RB
primary register and timer RB secondary register.
14.1 Overview
• Four operating modes
Timer mode: Counts either internal count sources or timer RA underflows.
Programmable waveform generation mode: Outputs any pulse widths continuously.
Programmable one-shot generation mode: Outputs one-shot pulses.
Programmable wait one-shot generation mode: Outputs delayed one-shot pulses.
• Selection of eight count sources
φ, φ/2, φ/4, φ/8, φ/32, φ/64, φ/128, or an underflow of timer RA
• An interrupt generated on an underflow of the timer RB counter
φ8
φ
Timer RA underflow
TCK[2:0]
bits
TSTART bit
Timer RB interrupt
Write to TSTOP
except in timer mode
Toggle flipflop
Q
Q
CLR
CK
TOPL
TRBO pin
TOCNT
φ2
φ4
φ32
φ64
φ128
TOSST bit
INOSEG bit
TRGB pin
TMOD[1:0] bits
Data bus
TCKCUT bit
INOSTG bit
Polarity
select
CounterCounter
Digital
filter
TRBPRE TRBSC TRBPR
TMOD[1:0] = B'10 or B'11
Prescaler
Timer counter
Figure 14.1 Block Diagram of Timer RB