Datasheet

Section 9 16-Bit Timer Pulse Unit (TPU)
Rev.7.00 Dec. 24, 2008 Page 299 of 698
REJ09B0074-0700
9.4 Interface to Bus Master
9.4.1 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 from 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 9.2.
H
L
TCNTH TCNTL
Internal data bus
Bus interface
Module
data bus
Bus
master
Figure 9.2 16-Bit Register Access Operation [Bus Master ↔ TCNT (16 Bits)]
9.4.2 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.
Examples of 8-bit register access operation are shown in figures 9.3 to 9.5.