Datasheet

Section 14 16-Bit Timer Pulse Unit (TPU)
Rev. 2.00 Jul. 04, 2007 Page 288 of 692
REJ09B0309-0200
14.4 Interface to CPU
14.4.1 16-Bit Registers
TCNT and TGR are 16-bit registers. As the data bus to the CPU is 16 bits wide, 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 14.2.
H
L
CPU
Upper 8 bits Lower 8 bits
Module data bus
Bus interface
Internal data bus
TCNT
Figure 14.2 16-Bit Register Access Operation [CPU ↔ TCNT (16 Bits)]
14.4.2 8-Bit Registers
Registers other than TCNT and TGR are 8-bit. They can be read and written to in 8-bit units.
Examples of 8-bit register access operation are shown in figure 14.3 and 14.4.
Bus interface
H
Internal data bus
L
CPU
Module data bus
TCR
Figure 14.3 8-Bit Register Access Operation [CPU ↔ TCR (Upper 8 Bits)]