249
10.3
CPU Interface
10.3.1
16-Bit Accessible Registers
The timer counters (TCNT), general registers A and B (GRA, GRB), and buffer registers A and B
(BRA, BRB) are 16-bit registers. The SH CPU can access these registers a word at a time using a
16-bit data bus. Byte access is also possible. Read and write operations performed on TCNT in
word units are shown in figures 10.6 and 10.7. Byte-unit read and write operations on TCNTH and
TCNTL are shown in figures 10.8 to 10.11.
TCNTH
TCNTL
H
L
Bus
interface
H
L
CPU
Internal data bus
Module
data bus
Figure 10.6 TCNT Access (CPU to TCNT (Word))
TCNTH
TCNTL
H
L
Bus
interface
H
L
CPU
Internal data bus
Module
data bus
Figure 10.7 TCNT Access (TCNT to CPU (Word))
TCNTH
TCNTL
H
L
Bus
interface
H
L
CPU
Internal data bus
Module
data bus
Figure 10.8 TCNT Access (CPU to TCNT (Upper Byte))
Summary of Contents for HD6417032
Page 21: ......
Page 35: ...xiv ...
Page 85: ...50 ...
Page 101: ...66 ...
Page 129: ...94 ...
Page 135: ...100 ...
Page 343: ...308 ...
Page 369: ...334 ...
Page 383: ...348 ...
Page 475: ...440 ...
Page 525: ...490 CK RAS CAS TRp TRc TRcc tRASD1 tRASD2 tCASD3 tCASD2 TRr tCSR Figure 20 18 Self Refresh ...
Page 578: ...543 CK RAS CAS TRp TRc TRcc tRASD1 tRASD2 tCASD3 tCASD2 TRr tCSR Figure 20 62 Self Refresh ...
Page 689: ...654 ...