BC41B143A-ds-003Pc CSR, BC41B143A-ds-003Pc Datasheet - Page 68

• Manufacturer Part Number: BC41B143A-ds-003Pc
• Description: Blue Core ROM Plug-n-Go
• Manufacturer: CSR

10.7.2 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 BlueCore4-ROM
Plug-n-Go is configured as PCM master, generating PCM_SYNC and PCM_CLK, then PCM_SYNC is 8-bits long.
When BlueCore4-ROM Plug-n-Go 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.
BlueCore4-ROM Plug-n-Go 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.
10.7.3 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.
As with Long Frame Sync, BlueCore4-ROM Plug-n-Go 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.
BC41B143A-ds-003Pc
PCM_SYNC
PCM_SYNC
PCM_OUT
PCM_OUT
PCM_CLK
PCM_CLK
PCM_IN
PCM_IN
Figure 10.20: Long Frame Sync (Shown with 8-bit Companded Sample)
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Figure 10.21: Short Frame Sync (Shown with 16-bit Sample)
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© Cambridge Silicon Radio Limited 2005
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