Reset_b引脚可以不接SWD接口上,但是这个引脚可作用于芯片解锁,所以我们一般推荐客户把这个Reset_b引脚也接到SWD仿真口。
关于上面提到的Reset_b用于解锁请看参考手册MKE06P80M48SF0RM的“18.3.7.2 Unsecuring the MCU using SWD”部分说明(如下图)
然后你的Reset_b引脚处理必须和K\L系列一样,上拉10K电阻、对地并100nF电容。
这一点在K系列快速参考指南KQRUG(Kinetis Peripheral Module Quick Reference User's Guide)的第二章节硬件要点“Chapter 2 General System Setup (Hardware Considerations)”的“2.1.3.4.1 RESET_b and NMI_b”部分就有提到:
2.1.3.4.1 RESET_b and NMI_b
The RESET_b pin, if enabled, must have a 100 nF capacitor close to the MCU for transient protection. The NMI_b pin, if enabled, must not have any capacitance connected to it. Each pin, when enabled as their default function, has a weak internal pullup, but an external 4.7 kΩ to 10 kΩ pullup is recommended. As with power pin filtering, it is recommended to minimize the ground loop for the capacitor and the VDD loop for the pullup resistor for these pins.
The RESET_b pin also has a configurable digital filter to reject potential noise on this input after power-up. The configuration bits are located in the RCM_RPFC register. While use of this filter may negate the need for the pullup and capacitor mentioned above, it is still recommended to use external filtering in electrically noisy environments.