KS57C2308/P2308/C2316/P2316

SAM47 INSTRUCTION SET

 

 

LDB — Load Bit

LDB(Continued)

Examples: 1. The carry flag is set and the data value at input pin P1.0 is logic zero. The following instruction clears the carry flag to logic zero.

LDB C,P1.0

2.The P1 address is FF1H and the L register contains the value 9H (1001B). The address (memb.7–2) is 111100B and (L.3–2) is 10B. The resulting address is 11110010B or FF2H and P2 is addressed. The bit value (L.1–0) is specified as 01B (bit 1).

LD

L,#9H

 

LDB

C,P1.@L

; P1.@L specifies P2.1 and C P2.1

3.The H register contains the value 2H and FLAG = 20H.3. The address for H is 0010B and for FLAG(3–0) the address is 0000B. The resulting address is 00100000B or 20H. The bit value is 3. Therefore, @H+FLAG = 20H.3.

FLAG

EQU 20H.3

 

LD

H,#2H

 

LDB

C,@H+FLAG

; C FLAG (20H.3)

4.The following instruction sequence sets the carry flag and the loads the "1" data value to the output pin P2.0, setting it to output mode:

SCF

;

C "1"

LDB P2.0,C

;

P2.0 "1"

5.The P1 address is FF1H and L = 9H (1001B). The address (memb.7–2) is 111100B and (L.3–

2)is 10B. The resulting address, 11110010B specifies P2. The bit value (L.1–0) is specified as 01B (bit 1). Therefore, P1.@L = P2.1.

SCF

 

;

C "1"

LD

L,#9H

 

 

LDB

P1.@L,C

;

P1.@L specifies P2.1

;P2.1 "1"

6.In this example, H = 2H and FLAG = 20H.3 and the address 20H is specified. Since the bit value is 3, @H+FLAG = 20H.3:

FLAG EQU 20H.3

RCF

;

C "0"

LD

H,#2H

 

LDB @H+FLAG,C

;

FLAG(20H.3) "0"

NOTE: Port pin names used in examples 4 and 5 may vary with different SAM47 devices.

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Image 139
Samsung KS57C2308 manual Flag EQU 20H.3 RCF, Ldb @H+Flag,C