witter1: 也是遇到同样的问题，证实

一只笨鸟: IEEE754标准中规定了尾数用23位来表示,但最多只能表示8388607，而不能全覆盖9999999，但能完整表示999999，故有效位是6位，但小于等于8388607又能准确表示，故有效位为6~7.

qq_45952535: 23位能表示最大的数不应该是2^23-1=8388607吗？不太能理解为啥是2^23

fanchenxinok: 楼主有遇到这种情况吗： Load "C:\\ti\\L42P-APP\\keil\\Objects\\L42P_APP_FW.axf" * JLink Info: Reset: Halt core after reset via DEMCR.VC_CORERESET. * JLink Info: Reset: Reset device via AIRCR.SYSRESETREQ. *** error 122: AGDI: memory read failed (0x01000020) * JLink Info: CPU could not be halted ***JLink Error: Cannot read register 15 (R15) while CPU is running ***JLink Error: Cannot read register 16 (XPSR) while CPU is running ***JLink Error: Cannot read register 0 (R0) while CPU is running ***JLink Error: Cannot read register 1 (R1) while CPU is running ***JLink Error: Cannot read register 2 (R2) while CPU is running ***JLink Error: Cannot read register 3 (R3) while CPU is running ***JLink Error: Cannot read register 4 (R4) while CPU is running ***JLink Error: Cannot read register 5 (R5) while CPU is running ***JLink Error: Cannot read register 6 (R6) while CPU is running ***JLink Error: Cannot read register 7 (R7) while CPU is running ***JLink Error: Cannot read register 8 (R8) while CPU is runn

一只笨鸟: 清除标志位或者把对应的中断服务函数写好啊