h8s2277 Renesas Electronics Corporation., h8s2277 Datasheet - Page 304

• Manufacturer Part Number: h8s2277
• Description: Hitachi Single-chip Microcomputer H8s/2276 Series
• Manufacturer: Renesas Electronics Corporation.

10.3
10.3.1
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 10.2.
10.3.2
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.
Examples of 8-bit register access operation are shown in figures 10.3, 10.4, and 10.5.
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Bus
master
Bus
master
Figure 10.3 8-Bit Register Access Operation [Bus Master
Figure 10.2 16-Bit Register Access Operation [Bus Master
Interface to Bus Master
16-Bit Registers
8-Bit Registers
Internal data bus
Internal data bus
H
L
H
L
Bus interface
Bus interface
TCNTH
TCR
TCR (Upper 8 Bits)]
TCNTL
TCNT (16 Bits)]
Module
data bus
Module
data bus