M16C80 Datasheet, PDF (117/358 Pages) Renesas Technology Corp – RENESAS 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/80 SERIES

M16C/80 Group
14. Timer B
14. Timer B
Figure 14.1 shows the block diagram of timer B. Figures 14.2 and 14.3 show the timer B-related registers.
Use the timer Bi mode register (i = 0 to 5) bits 0 and 1 to choose the desired mode.
Timer B has three operation modes listed as follows:
• Timer mode: The timer counts an internal count source.
• Event counter mode: The timer counts pulses from an external source or a timer overflow.
• Pulse period/pulse width measuring mode: The timer measures an external signal's pulse period or
pulse width.
Data bus high-order bits
Clock source selection
f1
f8
f32
fC32
• Timer
• Pulse period/pulse width measurement
• Event counter
Data bus low-order bits
Low-order 8 bits
Reload register (16)
High-order 8 bits
Counter (16)
TBiIN
(i = 0 to 5)
Polarity switching
and edge pulse
Can be selected in only
event counter mode
TBj overflow
(j = i – 1. Note, however,
j = 2 when i = 0,
j = 5 when i = 3)
Figure 14.1 Block diagram of timer B
Count start flag
(address 034016)
Counter reset circuit
TBi
Timer B0
Timer B1
Timer B2
Timer B3
Timer B4
Timer B5
Address
035116 035016
035316 035216
035516 035416
031116 031016
031316 031216
031516 031416
TBj
Timer B2
Timer B0
Timer B1
Timer B5
Timer B3
Timer B4
Timer Bi mode register
b7 b6 b5 b4 b3 b2 b1 b0
Symbol
Address
TBiMR(i = 0 to 5) 035B16 to 035D16
031B16 to 031D16
When reset
00XX00002
00XX00002
Bit symbol
TMOD0
TMOD1
MR0
MR1
MR2
Bit name
Function
Operation mode select bit
b1 b0
0 0 : Timer mode
0 1 : Event counter mode
1 0 : Pulse period/pulse width
measurement mode
1 1 : Must not be set
Function varies with each operation mode
MR3
TCK0
TCK1
Count source select bit
(Function varies with each operation mode)
Note 1: Timer B0, timer B3.
Note 2: Timer B1, timer B2, timer B4, timer B5.
Figure 14.2 Timer B-related registers (1)
R
W
(Note 1)
(Note 2)
Rev.1.00 Aug. 02, 2005 ^{Page 106} of 329
REJ09B0187-0100