HD404054 Datasheet, PDF (54/101 Pages) Hitachi Semiconductor – HMCS400-series microcomputers designed to increase program productivity with large-capacity memory

HD404054 Series/HD404094 Series
Timer D
Timer D Functions: Timer D has the following functions.
• Free-running/reload timer
• External event counter
• Timer output operation (toggle, 0, 1, and PWM outputs)
• Input capture timer
The block diagram for each operation mode of timer D is shown in figures 40-1 and 40-2.
Timer D Operations:
• Free-running/reload timer operation: The free-running/reload operation, input clock source, and
prescaler division ratio are selected by timer mode register D1 (TMD1: $010).
Timer D is initialized to the value set in timer write register D (TWDL: $011, TWDU: $012) by
software and incremented by one at each clock input. If an input clock is applied to timer D after it has
reached $FF, an overflow is generated. In this case, if the reload timer function is enabled, timer D is
initialized to its initial value set in timer write register D; if the free-running timer function is enabled,
the timer is initialized to $00 and then incremented again.
The overflow sets the timer D interrupt request flag (IFTD: $003, bit 0). IFTD is reset by software or
MCU reset. Refer to figure 3 and table 1 for details.
• External event counter operation: Timer D is used as an external event counter by selecting the
external event input as an input clock source. In this case, pin R4₀/EVND must be set to EVND by port
mode register C (PMRC: $025).
Either falling or rising edge, or both falling and rising edges of input signals can be selected as the
external event detection edge by detection edge select register 2 (ESR2: $027). When both rising and
falling edges detection is selected, the time between the falling edge and rising edge of input signals
must be 2t_cyc or longer.
Timer D is incremented by one at each detection edge selected by detection edge select register 2
(ESR2: $027). The other operation is basically the same as the free-running/reload timer operation.
• Timer output operation: The following four output modes can be selected for timer D by setting timer
mode register D2 (TMD2: $015).
Toggle
0 output
1 output
PWM output
By selecting the timer output mode, pin R3₂/TOD is set to TOD. The output from TOD is reset low by
MCU reset.
 Toggle output: The operation is basically the same as that of timer-C’s toggle output.
 0 output: The operation is basically the same as that of timer-C’s 0 output.
 1 output: The operation is basically the same as that of timer-C’s 1 output.
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