Functional Description
12-26
ADSP-BF537 Blackfin Processor Hardware Reference
2X Clock Recovery Control
The SPORTs can recover the data rate clock from a provided 2X input
clock. This enables the implementation of H.100 compatibility modes for
MVIP-90 (2 Mbps data) and HMVIP (8 Mbps data), by recovering
2 MHz from 4 MHz or 8 MHz from the 16 MHz incoming clock with
the proper phase relationship. A 2-bit mode signal (
MCCRM[1:0]
in the
SPORTx_MCMC2
register) chooses the applicable clock mode, which includes
a non-divide or bypass mode for normal operation. A value of
MCCRM = 00
chooses non-divide or bypass mode (H.100-compatible),
MCCRM = 10
chooses MVIP-90 clock divide (extract 2 MHz from 4 MHz), and
MCCRM = 11
chooses HMVIP clock divide (extract 8 MHz from 16 MHz).
Functional Description
The following sections provide a functional description of the SPORTs.
Clock and Frame Sync Frequencies
The maximum serial clock frequency (for either an internal source or an
external source) is
SCLK/2
. The frequency of an internally generated clock
is a function of the system clock frequency (
SCLK
) and the value of the
16-bit serial clock divide modulus registers,
SPORTx_TCLKDIV
and
SPORTx_RCLKDIV
.
TSCLKx frequency = (SCLK frequency)/(2 x (SPORTx_T 1))
RSCLKx frequency = (SCLK frequency)/(2 x (SPORTx_R 1))
If the value of
SPORTx_TCLKDIV
or
SPORTx_RCLKDIV
is changed while the
internal serial clock is enabled, the change in
TSCLK
or
RSCLK
frequency
takes effect at the start of the drive edge of
TSCLK
or
RSCLK
that follows the
next leading edge of
TFS
or
RFS
.
Summary of Contents for Blackfin ADSP-BF537
Page 42: ...Contents xlii ADSP BF537 Blackfin Processor Hardware Reference ...
Page 90: ...Development Tools 1 32 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 138: ...Programming Examples 4 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 340: ...SDC Programming Examples 6 84 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 606: ...Programming Examples 9 94 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 660: ...Programming Examples 10 54 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 720: ...Electrical Specifications 11 60 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 840: ...Programming Examples 13 42 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 876: ...Programming Examples 14 36 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 938: ...Programming Examples 15 62 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 958: ...Programming Examples 17 12 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 986: ...Programming Examples 18 28 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 1162: ...G 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 1218: ...Index I 56 ADSP BF537 Blackfin Processor Hardware Reference ...