问题以及解决!谢谢各位!

问题以及解决!谢谢各位!
问题产生的原因:

   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.

发表时间:2003年6月14日14:14:42

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34388.[详细]p2和p0口的资料您给我们也看看吧
摘要:......(无内容)
－ [alvinyang][1068次] 2003年6月14日

34391.[详细]AT89C2051没有P2和P0口！
摘要:Port 3 Port 3 pins P3.0 to P3.5, P3.7 are seven bi-ir......(909字)
－ [xiao_die][996次] 2003年6月14日

34387.[详细]那P2口和P0
摘要:......(无内容)
－ [alvinyang][952次] 2003年6月14日