软件问题:
xiaoxiaodie()写的很清楚!
When 1s are written to Port 1 pins, they can be used as inputs. When pins P1.2 to P1.7 are used as inputs and are externally pulled low, they will source current (I IL ) because of the internal pullups.
现在把P1口描叙如下:
Port 1
Port 1 is an 8-bit bi-irectional I/O port. Port pins P1.2 to P1.7 provide internal Pullups. P1.0 and P1.1 require exter-nal pullups. P1.0 and P1.1 also serve as the positive input (AIN0) and the negative input (AIN1), respectively, of the on-chip precision analog comparator. The Port 1 output buffers can sink 20 mA and can drive LED displays directly.When 1s are written to Port 1 pins, they can be used as inputs. When pins P1.2 to P1.7 are used as inputs and are externally pulled low, they will source current (I IL ) because of the internal pullups.
Port 1 also receives code data during Flash programming
and verification.
NOP
CLR RCLK
NOP
SETB RCLK
NOP
NOP
CLR RCLK
RET
;****************************************************************************
DSNEXT:
MOV R1,#08H
DDSP1:
NOP
CLR C ;右移出低位
RRC A
MOV DATA1,C
NOP
CLR SRCLK
NOP
SETB SRCLK
NOP
NOP
CLR SRCLK
DJNZ R1,DDSP1
RET
;***********************************************************
TABLE: DB 60H,0daH,0f2H,66H,0b6H,0beh,0e0H,0feH,0f6H ;1,2,3,4,5,6,7,8,9
;***************************************************************************
END