User's Manual

Bluegiga Technologies Oy
Page 27 of 52
PCM_OUT
PCM_IN
PCM_CLK
PCM_SYNC
Up to 2400kHz
8/48kHz
Figure 16: BT111 as PCM slave
14.1.2 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
BT111 is configured as PCM master, generating PCM_SYNC and PCM_CLK, then PCM_SYNC is 8 bits long.
When BT111 is configured as PCM Slave, PCM_SYNC is from 1 cycle PCM_CLK to half the PCM_SYNC
rate.
Figure 17: Long Frame Sync (Shown with 8-bit Companded Sample)
BT111 samples PCM_IN on the falling edge of PCM_CLK and transmits PCM_OUT on the rising edge.
PCM_OUT is configurable as high impedance on the falling edge of PCM_CLK in the LSB position or on the
rising edge.
14.1.3 Short Frame Sync
In Short Frame Sync, the falling edge of PCM_SYNC indicates the start of the PCM word. PCM_SYNC is
always 1 clock cycle long.