HD643303x Hitachi, HD643303x Datasheet - Page 222

• Manufacturer Part Number: HD643303x
• Description: Hitachi Microcomputer
• Manufacturer: Hitachi

8.3.2 8-Bit Accessible Registers
The registers other than the timer counters, general registers, and buffer registers are 8-bit
registers. These registers are linked to the CPU by an internal 8-bit data bus.
Figures 8-12 and 8-13 show examples of byte read and write access to a TCR.
If a word-size data transfer instruction is executed, two byte transfers are performed.
CPU
CPU
On-chip data bus
On-chip data bus
Figure 8-11 Access to Timer Counter (CPU Reads TCNT, Lower Byte)
H
L
H
L
Figure 8-12 TCR Access (CPU Writes to TCR)
Bus interface
Bus interface
207
TCNTH
TCR
TCNTL
H
L
H
L
Module
data bus
Module
data bus