问 对应接口上的一堆上拉和下拉电阻可以不安装吗?我只使用串口下载调试不用JTAG 答 1: 一般不能省。除非数据手册上说了，里面有内部电阻可以不外接。 答 2: 我见datasheet上这样写的On the LPC2101/02/03, the pins TMS, TCK, TDI, TDO, AND TRST are multiplexed with P0.27 - P0.31. To have them come up as a Debug port, connect a weak bias resistor (4.7-10 kΩ depending on the external JTAG circuitry) between VSS and the RTCK pin. To have them come up as GPIO pins, do not connect a bias resistor, and ensure that any external driver connected to Pin 26 (RTCK) is either driving high or is in high-impedance state during Reset.
如果按上面的说法是可以不用的 答 3: 作为GPIO时，不是不用接，而是不要接。如果要TMS,TCK,TDI,TDO,TRST作为GPIO时，RTCK要不就悬空，要不就接一个上拉电阻。