Writing to this register allows multiple channels to be enabled
or disabled simultaneously, so they can run in perfect sync.
For each channel, there is only one physical EN register bit,
which can be accessed through here or CHx_CSR.
CH0
reader -CH0
writer -CH1
reader -CH1
writer -CH2
reader -CH2
writer -CH3
reader -CH3
writer -CH4
reader -CH4
writer -CH5
reader -CH5
writer -CH6
reader -CH6
writer -CH7
reader -CH7
writer -EN
readerEN
writer