User's Manual

Bluegiga Technologies Oy
Page 26 of 40
Figure 16: PCM Interface Slave
9.2 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
WT11i is configured as PCM master, generating PCM_SYNC and PCM_CLK, then PCM_SYNC is 8-bits long.
When WT11i 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., 62.5s long.
Figure 17: Long Frame Sync (Shown with 8-bit Companded Sample)
WT11i 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.
9.3 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.