Epson S1C33L03 manual 192

II CORE BLOCK: BCU (Bus Control Unit)

Little-endian

31			Source (general-purpose register)									0					Bus operation
		Byte 3		Byte 2		Byte 1			Byte 0				No.	A1	A0	#WRH #WRL		15	Data bus		0
					8		2	0 8		1		0	1	∗	0	X	0	Data retained		Byte 0
													2	∗	1	X	0	Data retained		Byte 1
						A[1:0]=∗ 1			A[1:0]=∗		0
					Destination (8-bit device)													(X: Not connected/Unused)
	Big-endian
31			Source (general-purpose register)									0					Bus operation
		Byte 3		Byte 2		Byte 1			Byte 0				No.	A1	A0	#WRH #WRL		15	Data bus		0
					8		1	0 8		2		0	1	∗	0	0	0		Byte 1	Data retained
													2	∗	1	0	0		Byte 0	Data retained
						A[1:0]=∗ 0			A[1:0]=∗		1
					Destination (8-bit device)														(∗ : Uniformly 1 or 0)
					Figure 4.13 Half-word Data Writing to an 8-bit Device
	Little-endian
31		Destination (general-purpose register)										0					Bus operation
		Sign or Zero extension				Byte 1			Byte 0				No.	A1	A0	#WRH #WRL		15	Data bus		0
					8		2	0 8		1		0	1	∗	0	X	1		Ignored	Byte 0
													2	∗	1	X	1		Ignored	Byte 1
						A[1:0]=∗ 1			A[1:0]=∗		0
						Source (8-bit device)												(X: Not connected/Unused)
	Big-endian

31	Destination (general-purpose register)						0
	Sign or Zero extension	Byte 1			Byte 0
	8		1	0 8		2	0
		A[1:0]=∗ 0			A[1:0]=∗ 1

Bus operation

No.	A1	A0	#WRH #WRL 15		Data bus		0
1	∗	0	1	1	Byte 1	Ignored
2	∗	1	1	1	Byte 0	Ignored

(∗ : Uniformly 1 or 0)

Figure 4.14 Half-word Data Reading from an 8-bit Device

Little-endian

31

Source (general-purpose register)

0

Bus operation

Byte 3

Byte 2

Byte 1

Byte 0

No.

A1

A0

#WRH #WRL

15

Data bus

0

8

1

0

1

∗

∗

X

0

Data retained

Byte 0

A[1:0]=∗∗

Destination (8-bit device)

(X: Not connected/Unused)

Big-endian

31

Source (general-purpose register)

0

Bus operation

Byte 3

Byte 2

Byte 1

Byte 0

No.

A1

A0

#WRH #WRL

15

Data bus

0

8

1

0

1

∗

∗

0

1

Byte 0

Data retained

A[1:0]=∗∗

Destination (8-bit device)

Figure 4.15

Byte Data Writing to an 8-bit Device

Little-endian

31

Destination (general-purpose register)

0

Bus operation

Sign or Zero extension

Byte 0

No.

A1

A0

#WRH #WRL

15

Data bus

0

8

1

0

1

∗

∗

X

1

Ignored

Byte 0

A[1:0]=∗∗

Source (8-bit device)

(X: Not connected/Unused)

Big-endian

31

Destination (general-purpose register)

0

Bus operation

Sign or Zero extension

Byte 0

No.

A1

A0

#WRH #WRL

15

Data bus

0

8

1

0

1

∗

∗

1

1

Byte 0

Ignored

A[1:0]=∗∗

Source (8-bit device)

Figure 4.16 Byte Data Reading from an 8-bit Device

B-II-4-16 EPSON S1C33L03 FUNCTION PART