Keys and buzzer Control Based on fl2440 Development Board

Document directory

• Basic Principles:
• Logical operation commands:
•  
• Comparison command:

Basic Principles:

Logical operation commands:

And r0, R0, #0x01; R0 = R0 & 0x01 retrieve R0's percentile data

ORR r0, R0, # 0xff; R0 = R0 | 0xff

LSR logical shift right logic right shift

RX, LSR # N or RX, LSR, Rn

Register = register> shift

EOR logical exclusive or

EOR r0, R0, #3 reverse r0, 0 and 1 in

Bic (bit clear)

Bic r0, # % 0110; note that the binary format is %

Comparison command:

CMP R1, #10 compare and set CPSR

Tst

TEQ

Condition judgment mark:

 

 

Register address R/W description reset value
Gpfcon 0x56000050 R/W configures the pins of port F 0x0
Gpfdat 0x56000054 R/W the data register for port f undef.
Gpfup 0x56000058 R/W pull-up disable register for port F 0x000
Reserved 0x5620.5c ---

 

00 = input 01 = Output

1) set gpf0/2/3/4 to input

00 00 00 01 00

 

 

 

Area button, code, readonly

Entry


Start
Prohibit pull-up Resistance
LDR R1, = 0x56000058
LDR R2, = 0xff
STR R2, [R1]

; Set GPF0--GPF4 as input

LDR R3, = 0x56000050
LDR R4, = 0x55555404
STR R4, [R3]

; Set the corresponding port of the buzzer to the output
LDR R1, = 0x56000010
LDR R2, = 0x01
STR R2, [R1]

Loop
; Read data
LDR R3, = 0x56000054
LDR R4, [R3]; read data

; Determines whether a key is pressed
11100010
; Will be unique in the key-independent position 1

ORR R4, R4, #0xe2

CMP R4, # 0xff

Beq beep_down
B beep_on

B Loop
; Close the buzzer
Beep_down
LDR R1, = 0x56000014
LDR R2, = 0x0
STR R2, [R1]
B Loop

Beep_on
LDR R1, = 0x56000014
LDR R2, = 0x1
STR R2, [R1]
B Loop

End

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