单片机机的内存模式问题

只看该作者 · 2010-11-15 21:05

今天用AT89C51编了个程序,在程序中要查表,为什么表中的数据个数只有大约一百个才能编译通过,如果多了就通不过,改变了内存模式就行?
const uchar Font2[]={
/*--  文字:  0  --*/
/*--  宋体18;  此字体下对应的点阵为：宽x高=12x24 --*/
/*--  宽度不是8的倍数，现调整为：宽度x高度=16x24  --*/
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x0F,0x00,0x19,0x80,0x30,0xC0,
0x30,0xC0,0x60,0x60,0x60,0x60,0x60,0x60,0x60,0x60,0x60,0x60,0x60,0x60,0x60,0x60,
0x60,0x60,0x30,0xC0,0x30,0xC0,0x19,0x80,0x0F,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x0F,0x00,0x19,0x80,0x30,0xC0,
0x30,0xC0,0x60,0x60,0x60,0x60,0x60,0x60,0x60,0x60,0x60,0x60,0x60,0x60,0x60,0x60,
0x60,0x60,0x30,0xC0,0x30,0xC0,0x19,0x80,0x0F,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x0F,0x00,0x19,0x80,0x30,0xC0,
0x30,0xC0,0x60,0x60,0x60,0x60,0x60,0x60,0x60,0x60,0x60,0x60,0x60,0x60,0x60,0x60,
0x60,0x60,0x30,0xC0,0x30,0xC0,0x19,0x80,0x0F,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
};

1万 · 2010-11-15 21:17

const uchar code Font2[]即可
单片机RAM极其宝贵啊,51不同的RAM空间大小不一,访问方法,效率也不一样
DATA空间128字节
SFR空间128字节
IDATA空间256字节,其中128与DATA重叠
XDATA空间64K字节
PDATA空间256字节,共256页,与XDATA重叠
...
不同的编译模式将变量定位在不同的空间(除非特别指定),如果超过相应空间限制自然会出错了
...