Table of Contents
Advertisement
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.
Internal data bus
H
Bus
L
master
Figure 10.2 16-Bit Register Access Operation [Bus Master ↔
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 to 10.5.
Internal data bus
H
Bus
L
master
Figure 10.3 8-Bit Register Access Operation [Bus Master ↔
Bus interface
Bus interface
TCNTH
TCNTL
↔ TCNT (16 Bits)]
↔ ↔
TCR
↔ TCR (Upper 8 Bits)]
↔ ↔
Rev. 3.0, 10/02, page 291 of 686
Module
data bus
Module
data bus
Advertisement
Table of Contents
