HD404849 Datasheet, PDF (73/125 Pages) Hitachi Semiconductor – 4-Bit Single-Chip Microcomputer

HD404849 Series
By selecting the input capture operation, pin R1₂/TOD is set to R1₂ and timer D is reset to $00.
Registers for Timer D Operation: By using the following registers, timer D operation modes are selected
and the timer D count is read and written.
 Timer mode register D1 (TMD1: $010)
 Timer mode register D2 (TMD2: $015)
 Timer write register D (TWDL: $011, TWDU: $012)
 Timer read register D (TRDL: $011, TRDU: $012)
 Port mode register C (PMRC: $025)
 Detection edge select register 2 (ESR2: $027)
• Timer mode register D1 (TMD1: $010): Four-bit write-only register that selects the free-running/reload
timer function, input clock source, and prescaler division ratio as shown in figure 59. 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 D1 (TMD1: $010) write instruction. A timer D initialization by writing to
timer write register D (TWDL: $011, TWDU: $012) must be programmed to occur after a mode change
becomes valid.
When selecting the input capture timer operation, select the internal clock as the input clock source.
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