Datasheet

Section 10 16-Bit Timer Pulse Unit (TPU)
Rev. 3.00 Sep. 28, 2009 Page 265 of 910
REJ09B0350-0300
10.4 Interface to Bus Master
10.4.1 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 10.2.
H
L
TCNTH TCNTL
Internal data bus
Bus interface
Module
data bus
Bus
master
Figure 10.2 16-Bit Register Access Operation [Bus Master ↔ TCNT (16 Bits)]
10.4.2 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 10.3, 10.4, and 10.5.