Specifications

52
PCM_OUT
PCM_IN
PCM_CLK
PCM_SYNC
8kHz
Up to 2048kHz
WT12
WTxx
Figure 26: WT32 as PCM slave
7.4.2 Long Frame Sync
Long Frame Sync is the name given to a clocking format that controls the transfer of PCM
data words or samples. In Long Frame Sync, the rising edge of PCM_SYNC indicates the
start of the PCM word. When WT32 is configured as PCM Master, generating PCM_SYNC
and PCM_CLK, then PCM_SYNC is 8-bits long. When BlueCore4-External is configured as
PCM Slave, PCM_SYNC may be from two consecutive falling edges of PCM_CLK to half the
PCM_SYNC rate, i.e. 62.5s long.
WT32 samples PCM_IN on the falling edge of PCM_CLK and transmits PCM_OUT on the
rising edge. PCM_OUT may be configured to be high impedance on the falling edge of
PCM_CLK in the LSB position or on the rising edge.
1
2345678PCM_OUT
PCM_CLK
PCM_SYNC
1
2345678
undefined undefined
PCM_IN
Figure 27: Long frame sync (shown with 8-bit companded sample)
7.4.3 Short Frame Sync
In Short Frame Sync, the falling edge of PCM_SYNC indicates the start of the PCM word.
PCM_SYNC is always one clock cycle long.