Epson S1C33210 manual 167

II CORE BLOCK: BCU (Bus Control Unit)

Little-endian

31			Destination (general-purpose register)										0					Bus operation
		Byte 3			Byte 2			Byte 1			Byte 0			No.	A1	A0	#WRH #WRL		15	Data bus		0
8			4	0 8		3	0 8		2	0 8		1	0	1	0	0	X	1		Ignored	Byte 0
														2	0	1	X	1		Ignored	Byte 1
		A[1:0]=11			A[1:0]=10			A[1:0]=01			A[1:0]=00
														3	1	0	X	1		Ignored	Byte 2
					Source (8-bit device)
														4	1	1	X	1		Ignored	Byte 3
	Big-endian																		(X: Not connected/Unused)
31			Destination (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 8		3	0 8		4	0	1	0	0	1	1		Byte 3	Ignored
														2	0	1	1	1		Byte 2	Ignored
		A[1:0]=00			A[1:0]=01			A[1:0]=10			A[1:0]=11
														3	1	0	1	1		Byte 1	Ignored
					Source (8-bit device)
														4	1	1	1	1		Byte 0	Ignored

Figure 4.12 Word Data Reading from an 8-bit Device

Little-endian

31		Source (general-purpose register)								0
	Byte 3		Byte 2	Byte 1				Byte 0
		8			2	0 8				0
									1
				A[1:0]=∗ 1			A[1:0]=∗ 0

Destination (8-bit device)

Big-endian

Bus operation

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

(X: Not connected/Unused)

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

S1C33210 FUNCTION PART

EPSON

B-II-4-15