Epson S1C33210 - Manual (Page 167)

II CORE BLOCK: BCU (Bus Control Unit)
S1C33210 FUNCTION PART EPSON B-II-4-15
Ignored
15 Data bus 0 #WRL
1
1
1
1
#WRH
X
X
X
X
A0
0
1
0
1
A1
0
0
1
1
No.
1
2
3
4 Byte 0
Ignored Byte 1
Ignored Byte 2
Ignored Byte 3
Byte 3 Byte 2 Byte 1 Byte 0
31 0
A[1:0]=10 A[1:0]=00 A[1:0]=11 A[1:0]=01
8 0
1 4
8 8 8 0 0 0
3 2
Bus operation
(X: Not connected/Unused)
Destination (general-purpose register)
Source (8-bit device)
Little-endian
Byte 3
15 Data bus 0 #WRL
1
1
1
1
#WRH
1
1
1
1
A0
0
1
0
1
A1
0
0
1
1
No.
1
2
3
4 Ignored
Byte 2 Ignored
Byte 1 Ignored
Byte 0 Ignored
Byte 3 Byte 2 Byte 1 Byte 0
31 0
A[1:0]=01 A[1:0]=11 A[1:0]=00 A[1:0]=10
8 0
4 1
8 8 8 0 0 0
2 3
Bus operation Destination (general-purpose register)
Source (8-bit device)
Big-endian
Figure 4.12 Word Data Reading from an 8-bit Device
Data retained
15 Data bus 0 #WRL
0
0
#WRH
X
X
A0
0
1
A1
∗
∗
No.
1
2 Byte 0
Data retained Byte 1
Byte 3 Byte 2 Byte 1 Byte 0
31 0
A[1:0]= ∗ 0 A[1:0]= ∗ 1
0
1
8 8 0
Source (general-purpose register)
Destination (8-bit device)
2
Bus operation
(X: Not connected/Unused)
Little-endian
Byte 1
15 Data bus 0 #WRL
0
0
#WRH
0
0
A0
0
1
A1
∗
∗
No.
1
2 Data retained
Byte 0 Data retained
Byte 3 Byte 2 Byte 1 Byte 0
31 0
A[1:0]=
∗
1 A[1:0]=
∗
0
0
2
8 8 0
Source (general-purpose register)
Destination (8-bit device)
1
Bus operation
(
∗
: Uniformly 1 or 0)
Big-endian
Figure 4.13 Half-word Data Writing to an 8-bit Device
Ignored
15 Data bus 0 #WRL
1
1
#WRH
X
X
A0
0
1
A1
∗
∗
No.
1
2 Byte 0
Ignored Byte 1
Byte 1 Byte 0
31 0
A[1:0]=
∗
0 A[1:0]=
∗
1
0
1
8 8 0
2
Bus operation
(X: Not connected/Unused)
Destination (general-purpose register)
Source (8-bit device)
Sign or Zero extension
Little-endian
Byte 1
15 Data bus 0 #WRL
1
1
#WRH
1
1
A0
0
1
A1
∗
∗
No.
1
2 Ignored
Byte 0 Ignored
Byte 1 Byte 0
31 0
A[1:0]=
∗
1 A[1:0]=
∗
0
0
2
8 8 0
1
Bus operation Destination (general-purpose register)
Sign or Zero extension
Big-endian
(
∗
: Uniformly 1 or 0)
Figure 4.14 Half-word Data Reading from an 8-bit Device
Data retained
15 Data bus 0 #WRL
0
#WRH
X
A0
∗
A1
∗
No.
1 Byte 0
Byte 3 Byte 2 Byte 1 Byte 0
31 0
A[1:0]= ∗∗
0
1
8
Source (general-purpose register)
Destination (8-bit device)
Bus operation
(X: Not connected/Unused)
Little-endian
Byte 0
15 Data bus 0 #WRL
1
#WRH
0
A0
∗
A1
∗
No.
1 Data retained
Byte 3 Byte 2 Byte 1 Byte 0
31 0
A[1:0]= ∗∗
0
1
8
Source (general-purpose register)
Destination (8-bit device)
Bus operation
Big-endian
Figure 4.15 Byte Data Writing to an 8-bit Device