HD6432633 Datasheet, PDF (606/1453 Pages) Renesas Technology Corp – Series of Microcomputers (MCUs: microcomputer units)

11.3 Interface to Bus Master
11.3.1 16-Bit Registers
TCNT and TGR are 16-bit registers. As the data bus to the bus master is 16 bits wide, these
registers can be read and written to in 16-bit units.
These registers cannot be read or written to in 8-bit units; 16-bit access must always be used.
An example of 16-bit register access operation is shown in figure 11-2.
Internal data bus
H
Bus
master ^L
Bus interface
Module
data bus
TCNTH
TCNTL
Figure 11-2 16-Bit Register Access Operation [Bus Master ↔ TCNT (16 Bits)]
11.3.2 8-Bit Registers
Registers other than TCNT and TGR are 8-bit. As the data bus to the CPU is 16 bits wide, these
registers can be read and written to in 16-bit units. They can also be read and written to in 8-bit
units.
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