RA3我没有使用，专门作为复位用。

QQ图片20130621144321.jpg (269.91 KB, 下载次数: 1)

下载附件

2013-6-21 14:44 上传

总算把LCD点亮了！

原来是数字口，模拟口的问题。

Generally speaking, mcus have alternate uses for any pin. Sometimes, the power-on state / mode is not (digital) GPIO - PICs as you have found out power up in the analog mode. Other PICs may also default some of their pins for comparators.

Many PICs provide a gpio initialization sequence in the GPIO section of the datasheet, or to identify all relevant registers / bits, etc.

I always execute a routine, called mcu_init(), as the first user-space routine to reset the pins to digital IO. On some mcus, that routine could be an empty routines - AVRs for example. But it is a good idea to always have that.

millwood0 发表于 2013-6-22 06:07
Generally speaking, mcus have alternate uses for any pin. Sometimes, the power-on state / mode is  ...

原来，手册上的引脚功能说明中，有标ANx的IO都是带有模拟输入功能的，必须将其设置为数字输出。

xiongh 发表于 2013-6-15 15:28
看手册：

12.2 PORTA 寄存器

在学习中断，发现无论是定时器0还是定时器1还是其它，
中断程序都是这个：
void interrupt isr(void)
｛

  ｝

不像51单片机那样带有中断号来对应中断源。

难道PIC的所有中断程序都写在void interrupt isr(void)里，然后用判断语句来识别中断源吗？