在EPWM模块的CC模块中，CMPA有一个加载模式设置：
LOADAMODE
Active Counter-Compare A (CMPA) Load From Shadow Select Mode. This bit has no effect in immediate mode (CMPCTL[SHDWAMODE] = 1).
00 Load on CTR = Zero: Time-base counter equal to zero (TBCTR = 0x0000)
01 Load on CTR = PRD: Time-base counter equal to period (TBCTR = TBPRD)
10 Load on either CTR = Zero or CTR = PRD
11 Freeze (no loads possible)
我想确定一下，冻结模式，是不是指CMPA不再从其阴影寄存器中加载值了？ 保持当前值一直运行？
