AT89S51_8位微控制器的在系统可编程Flash_4K字节，很好的学习资料，快来下载学习吧。

文档内容节选

Features Compatible with MCS51 Products cid127 4K Bytes of InSystem Programmable ISP Flash Memory Endurance 1000 WriteErase Cycles cid127 40V to 55V Operating Range cid127 Fully Static Operation 0 Hz to 33 MHz cid127 Threelevel Program Memory Lock cid127 128 x 8bit Internal RAM cid127 32 Programmable IO Lines cid127 Two 16bit TimerCounters cid127 Six Interrupt Sources cid127 Full Duplex UART Serial Channel cid127 Lowpower Idle and Powerdown Modes cid127 Interrupt Recovery from Powerdown Mode c......