下面是我写的EM78P510N的4×5行列键盘扫描程序，20ms循环一次，
其中：k1,k2,k3,k4为输出，复用4个LED；ka,kb,kc,kd,ke为输入，外部上拉。
拿出来希望大家多扔点砖头过来，以便提高改进。
readkey: ;20ms扫描一次,说明:扫描到的键值没有来得及
;发送时又扫描到其他键值时,会被覆盖掉
bank 0
bc port7,led_con ;扫描前关闭指示灯使能端
mov a,port9
mov port9_buff,a ;保存指示灯状态
nop
bc port9,k1 ;扫描第一行
bs port9,k2
bs port9,k3
bs port9,k4
mov a,@1
mov key_databuff,a ;先假定为1
nop
nop
nop
nop
nop
nop
jbs porta,ka
jmp first_read_k_over
inc key_databuff
jbs porta,kb
jmp first_read_k_over
inc key_databuff
jbs porta,kc
jmp first_read_k_over
inc key_databuff
jbs porta,kd
jmp first_read_k_over
inc key_databuff
jbs porta,ke
jmp first_read_k_over
inc key_databuff
;;;;;;;;;;;;;;;;;;;;;
bs port9,k1 ;扫描第二行
bc port9,k2
bs port9,k3
bs port9,k4
nop
nop
nop
nop
nop
nop
nop
nop
jbs porta,ka
jmp first_read_k_over
inc key_databuff
jbs porta,kb
jmp first_read_k_over
inc key_databuff
jbs porta,kc
jmp first_read_k_over
inc key_databuff
jbs porta,kd
jmp first_read_k_over
inc key_databuff
jbs porta,ke
jmp first_read_k_over
inc key_databuff
;;;;;;;;;;;;;;;;;;;;;
bs port9,k1 ;扫描第三行
bs port9,k2
bc port9,k3
bs port9,k4
nop
nop
nop
nop
nop
nop
nop
nop
jbs porta,ka
jmp first_read_k_over
inc key_databuff
jbs porta,kb
jmp first_read_k_over
inc key_databuff
jbs porta,kc
jmp first_read_k_over
inc key_databuff
jbs porta,kd
jmp first_read_k_over
inc key_databuff
jbs porta,ke
jmp first_read_k_over
inc key_databuff
;;;;;;;;;;;;;;;;;;;;;
bs port9,k1 ;扫描第四行
bs port9,k2
bs port9,k3
bc port9,k4
nop
nop
nop
nop
nop
nop
nop
nop
jbs porta,ka
jmp first_read_k_over
inc key_databuff
jbs porta,kb
jmp first_read_k_over
inc key_databuff
jbs porta,kc
jmp first_read_k_over
inc key_databuff
jbs porta,kd
jmp first_read_k_over
inc key_databuff
jbs porta,ke
jmp first_read_k_over
nokey:
clr key_databuff ;无键
bc keyflag,keydown ;按键按下标志
bank 2
clr key_datalast
clr keydown_cnt
jmp readkey_out
first_read_k_over:
bank 0 ;复合键判断
bs port9,k1 ;扫描第三行
bs port9,k2
bc port9,k3
bs port9,k4
nop
nop
nop
nop
nop
nop
nop
nop
jbc porta,ke
jmp first_read_k_over_0
bs port9,k1 ;扫描第四行
bs port9,k2
bs port9,k3
bc port9,k4
nop
nop
nop
nop
nop
nop
nop
nop
jbc porta,ke
jmp first_read_k_over_0
mov a,@21
mov key_databuff,a
jmp first_read_k_over_1 ;是紧急按钮则直接跳到1,不经过有键按下检查
first_read_k_over_0:
jbc keyflag,keydown
jmp readkey_out ;确定有普通键按下时(已发送)不响应其他按键
;------------------------
mov a,key_databuff
jbc status,z
jmp nokey
sub a,@21
jbs status,c
jmp nokey
;------------------------检查键值是否在1－21范围内,防止出错
first_read_k_over_1:
mov a,key_databuff
bank 2
xor a,key_datalast
jbs status,z
jmp key_different ;键值与前一次不同
inc keydown_cnt ;键值与上一次相同,则计相同次数
mov a,@4 ;是否连续有相同按键4次
sub a,keydown_cnt
jbs status,c
jmp readkey_out
clr keydown_cnt
bank 0
;---------------------------
bs keyflag,keydown ;有键按下状态标志(确定有键)
bs uart_sendflag2,key_send ;uart使用请求标志,申请使用uart
mov a,key_databuff
lcall key_table ;键值转换
mov key_data_uartsend_buff,a
;---------------------------------------------------------
jmp readkey_out
key_different:
bank 0
mov a,key_databuff
bank 2
mov key_datalast,a ;与上次不同,保存当前键值
clr keydown_cnt
jmp readkey_out
readkey_out:
bank 0
bc port9,k1
bc port9,k2
bc port9,k3
bc port9,k4 ;停止行输出
bs port7,led_con ;扫描后打开指示灯使能端
mov a,port9_buff
mov port9,a ;恢复指示灯状态
ret |
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