HD404629R Datasheet, PDF (67/157 Pages) Renesas Technology Corp – AS Microcomputer Incorporating a DTMF Generator Circuit

HD404629R Series
Registers for Timer B Operation: By using the following registers, timer B operation modes are selected
and the timer B count is read and written.
 Timer mode register B1 (TMB1: $009)
 Timer mode register B2 (TMB2: $013)
 Timer write register B (TWBL: $00A, TWBU: $00B)
 Timer read register B (TRBL: $00A, TRBU: $00B)
 Port mode register C (PMRC: $025)
• Timer mode register B1 (TMB1: $009):
Four-bit write-only register that selects the free-running/reload timer function, input clock source, and
the prescaler division ratio as shown in figure 47. It is reset to $0 by MCU reset.
Writing to this register is valid from the second instruction execution cycle after the execution of the
previous timer mode register B1 write instruction. Setting timer B’s initialization by writing to timer
write register B (TWBL: $00A, TWBU: $00B) must be done after a mode change becomes valid.
Timer mode register B1 (TMB1: $009)
Bit
Initial value
Read/Write
Bit name
3
0
W
TMB13
2
0
W
TMB12
1
0
W
TMB11
0
0
W
TMB10
Free-running/reload
TMB13 timer selection
0
Free-running timer
1
Reload timer
Input clock period and input
TMB12 TMB11 TMB10 clock source
0
0
0
2048t_cyc
1
512t_cyc
1
0
128t_cyc
1
32t_cyc
1
0
0
8t_cyc
1
4t_cyc
1
0
2t_cyc
1
R1₃/EVNB (external event input)
Figure 47 Timer Mode Register B1 (TMB1)
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