Epson S1C33L03 manual 190

II CORE BLOCK: BCU (Bus Control Unit)

For information on memory connection, see Figure 4.18.

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
15				2		0	15		1			0	1	0	0	0	0		Byte 1	Byte 0
													2	1	0	0	0		Byte 3	Byte 2
		A[1:0]=10						A[1:0]=00
					Destination (16-bit device)
	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
15				1		0	15		2			0	1	0	0	0	0		Byte 3	Byte 2
													2	1	0	0	0		Byte 1	Byte 0
		A[1:0]=00						A[1:0]=10
					Destination (16-bit device)
								Figure 4.5 Word Data Writing to a 16-bit Device
	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
15					2	0	15			1		0	1	0	0	1	1		Byte 1	Byte 0
													2	1	0	1	1		Byte 3	Byte 2
		A[1:0]=10						A[1:0]=00
					Source (16-bit device)
	Big-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
15					1	0	15			2		0	1	0	0	1	1		Byte 3	Byte 2
													2	1	0	1	1		Byte 1	Byte 0
		A[1:0]=00						A[1:0]=10
					Source (16-bit device)
							Figure 4.6 Word Data Reading from a 16-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
							15		1			0	1	∗	0	0	0		Byte 1	Byte 0
								A[1:0]=∗ 0
							Destination (16-bit device)
	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
							15		1			0	1	∗	0	0	0		Byte 1	Byte 0
								A[1:0]=∗ 0
							Destination (16-bit device)
							Figure 4.7 Half-word Data Writing to a 16-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
							15			1		0	1	∗	0	1	1		Byte 1	Byte 0
								A[1:0]=∗ 0
								Source (16-bit device)
	Big-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
							15			1		0	1	∗	0	1	1		Byte 1	Byte 0
								A[1:0]=∗ 0
								Source (16-bit device)

Figure 4.8 Half-word Data Reading from a 16-bit Device

B-II-4-14 EPSON S1C33L03 FUNCTION PART