HD404889_03 Datasheet, PDF (89/197 Pages) Renesas Technology Corp – Low-Voltage AS Microcomputers with On-Chip LCD Circuit

HD404889/HD404899/HD404878/HD404868 Series
Timer B Registers
Timer B operation setting and timer B value reading/writing is controlled by the following registers.
Timer mode register B1 (TMB1: $010)
Timer mode register B2 (TMB2: $011)
Timer write register B (TWBL: $012, TWBU: $013)
Timer read register B (TRBL: $012, TRBU: $013)
Port mode register 2 (PMR2: $00A)
Module standby register 1 (MSR1: $00D)
• Timer mode register B1 (TMB1: $010):
Timer mode register B1 (TMB1) is a 4-bit write-only register, used to select free-running/reload timer
operation and the input clock as shown in figure 39.
Timer mode register B1 (TMB1) is reset to $0 by an MCU reset:
A modification of timer mode register B1 (TMB1) becomes effective after execution of two instructions
following the timer mode register B1 (TMB1) write instruction. The program must provide for timer B
initialization by writing to timer write register B (TWBL, TWBU) to be executed after the post-
modification mode has become effective.
Timer mode register B1 (TMB1: $010)
Bit
Read/Write
Initial value on reset
Bit name
3
W
0
TMB13
2
W
0
TMB12
1
W
0
TMB11
0
W
0
TMB10
TMB12 TMB11
0
0
1
0
1
1
TMB10
0
1
0
1
0
1
0
1
Input clock period and input clock source
2,048 tcyc
512 tcyc
128 tcyc
32 tcyc
8 tcyc
4 tcyc
2 tcyc
R10/EVNB (external event input)
TMB13
0
1
Free-running/reload timer
Free-running timer
Reload timer
Figure 39 Timer Mode Register B1 (TMB1)
Rev.6.00, Sep.08.2003, page 89 of 197