HD6432646 Hitachi, HD6432646 Datasheet - Page 370

• Manufacturer Part Number: HD6432646
• Description: (HD64F264x Series) 16-Bit Microcomputer
• Manufacturer: Hitachi

10.3
10.3.1
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.
10.3.2
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.
336
Bus
master
Figure 10-2 16-Bit Register Access Operation [Bus Master
Interface to Bus Master
16-Bit Registers
8-Bit Registers
Internal data bus
H
L
Bus interface
TCNTH
TCNTL
TCNT (16 Bits)]
Module
data bus