Interface To Bus Master; 16-Bit Registers - Renesas H8S/2633 Series Hardware Manual

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
L
master
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.
552
Bus interface
TCNTH TCNTL
Module
data bus