Epson CMOS 32-Bit Single Chip Microcomputer S1C33L03 - Page 190

II CORE BLOCK: BCU (Bus Control Unit)
B-II-4-14 EPSON S1C33L03 FUNCTION PART
For information on memory connection, see Figure 4.18.
Byte 1
15 Data bus 0#WRL
0
0
#WRH
0
0
A0
0
0
A1
0
1
No.
1
2
Byte 0
Byte 3 Byte 2
Byte 3 Byte 2 Byte 1 Byte 0
31 0
A[1:0]=10 A[1:0]=00
15 0
12
150
Source (general-purpose register)
Destination (16-bit device)
Bus operation
Little-endian
Byte 3
15 Data bus 0#WRL
0
0
#WRH
0
0
A0
0
0
A1
0
1
No.
1
2
Byte 2
Byte 1 Byte 0
Byte 3 Byte 2 Byte 1 Byte 0
31 0
A[1:0]=00 A[1:0]=10
15 0
21
150
Source (general-purpose register)
Destination (16-bit device)
Bus operation
Big-endian
Figure 4.5 Word Data Writing to a 16-bit Device
Byte 1
15 Data bus 0#WRL
1
1
#WRH
1
1
A0
0
0
A1
0
1
No.
1
2
Byte 0
Byte 3 Byte 2
Bus operation
12
Byte 3 Byte 2 Byte 1 Byte 0
31 0
Destination (general-purpose register)
A[1:0]=10 A[1:0]=00
Source (16-bit device)
15 0150
Little-endian
Byte 3
15 Data bus 0#WRL
1
1
#WRH
1
1
A0
0
0
A1
0
1
No.
1
2
Byte 2
Byte 1 Byte 0
Bus operation
21
Byte 3 Byte 2 Byte 1 Byte 0
31 0
Destination (general-purpose register)
A[1:0]=00 A[1:0]=10
Source (16-bit device)
15 0150
Big-endian
Figure 4.6 Word Data Reading from a 16-bit Device
Byte 1
15 Data bus 0#WRL
0
#WRH
0
A0
0
A1
∗
No.
1 Byte 0
Byte 3 Byte 2 Byte 1 Byte 0
31 0
A[1:0]= ∗ 0
0
1
15
Source (general-purpose register)
Destination (16-bit device)
Bus operation
Little-endian
Byte 1
15 Data bus 0#WRL
0
#WRH
0
A0
0
A1
∗
No.
1 Byte 0
Byte 3 Byte 2 Byte 1 Byte 0
31 0
A[1:0]= ∗ 0
0
1
15
Source (general-purpose register)
Destination (16-bit device)
Bus operation
Big-endian
Figure 4.7 Half-word Data Writing to a 16-bit Device
Byte 1
15 Data bus 0#WRL
1
#WRH
1
A0
0
A1
∗
No.
1 Byte 0
Bus operation
1
Sign or Zero extension Byte 1 Byte 0
31 0
Destination (general-purpose register)
A[1:0]= ∗ 0
Source (16-bit device)
015
Little-endian
Byte 1
15 Data bus 0#WRL
1
#WRH
1
A0
0
A1
∗
No.
1 Byte 0
Bus operation
1
Sign or Zero extension Byte 1 Byte 0
31 0
Destination (general-purpose register)
A[1:0]= ∗ 0
Source (16-bit device)
015
Big-endian
Figure 4.8 Half-word Data Reading from a 16-bit Device