D12320VF25IV Datasheet, PDF (513/1304 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

10.3 Interface to Bus Master
Section 10 16-Bit Timer Pulse Unit (TPU)
10.3.1 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 10.2.
Internal data bus
H
Bus
master ^L
Bus interface
Module
data bus
TCNTH
TCNTL
Figure 10.2 16-Bit Register Access Operation [Bus Master ↔ TCNT (16 Bits)]
10.3.2 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.
Examples of 8-bit register access operation are shown in figures 10.3 to 10.5.
Rev.6.00 Sep. 27, 2007 Page 481 of 1268
REJ09B0220-0600