BC352239A Datasheet, PDF (79/116 Pages) List of Unclassifed Manufacturers – BlueCore 3-Multimedia External

Device Terminal Descriptions
8.8.11 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
BlueCore3-Multimedia External is configured as PCM Master, generating PCM_SYNC and PCM_CLK, then
PCM_SYNC is 8-bits long. When BlueCore3-Multimedia 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. 62.5µs long.
PCM_SYNC
PCM_CLK
PCM_OUT
1
23
45
6
78
PCM_IN
Undefined
1
23
4
56
7
8 Undefined
Figure 8.13: Long Frame Sync (Shown with 8-bit Companded Sample)
BlueCore3-Multimedia External 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.
8.8.12 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.
PCM_SYNC
PCM_CLK
PCM_OUT
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
PCM_IN Undefined 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Undefined
Figure 8.14: Short Frame Sync (Shown with 16-bit Sample)
As with Long Frame Sync, BlueCore3-Multimedia External 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.
BC352239A-ds-001Pc
© Cambridge Silicon Radio Limited 2004
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