ADSP-BF535 Blackfin Processor Hardware Reference
11-65
Serial Port Controllers
The channel select offset mode is bit 4 in the
SPORTx_MCMC2
register. When
this mode is selected, the first bit of the
SPORTx_MTCSx
or
SPORTx_MRCSx
register is linked to the first bit directly following the offset of the win-
dow. If the channel select offset mode is not enabled, the first bit of the
SPORTx_MTCSx
or
SPORTx_MRCSx
register is placed at offset 0.
The 7-bit
CHNL
field in the
SPORTx_STAT
register indicates which channel is
currently selected during multichannel operation. This field is a read-only
status indicator.
CHNL[6:0]
increments by one as each channel is serviced,
and in channel select offset mode the value of
CHNL
is reset to 0 after the
offset has been completed. So, as an example, for a window of 8 and an
offset of 21, the counter displays a value between 0 and 28 in the regular
mode, but in channel select offset mode the counter resets to 0 after
counting up to 21 and the frame completes when the
CHNL
reaches a value
of 7, indicating the eighth channel.
The
FSDR
bit in the
SPORTx_MCMC2
register changes the timing relationship
between the frame sync and the clock received. This change enables the
SPORT to comply with the H.100 protocol.
Normally (
FSDR=0
), the data is transmitted on the same edge that the
TFS
is generated. For example, a positive edge
TFS
causes data to be transmit-
ted on the positive edge of the
SCK
, either the same edge or the following
one, depending on when
LATFS
is set.
When the frame sync/data relationship is used (
FSDR=1
), the frame sync is
expected to change on the falling edge of the clock and is sampled on the
rising edge of the clock. This is true even though data received is sampled
on the negative edge of the receive clock
Channel Selection Registers
A channel is a multibit word from 3 to 16 bits in length that belongs to
one of the TDM channels. Specific channels can be individually enabled
or disabled to select which words are received and transmitted during mul-
tichannel communications. Data words from the enabled channels are
Содержание ADSP-BF535 Blackfin
Страница 80: ...Development Tools 1 26 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 312: ...Working With Memory 6 86 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 332: ...System Interfaces 7 20 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 360: ...Dynamic Power Management Controller 8 28 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 446: ...Beginning and Ending an SPI Transfer 10 40 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 522: ...Timing Examples 11 76 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 562: ...IrDA Support 12 40 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 608: ...PCI I O Issues 13 46 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 672: ...References 14 64 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 810: ...SDRAM Controller SDC 18 86 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 811: ...ADSP BF535 Blackfin Processor Hardware Reference 18 87 External Bus Interface Unit...
Страница 812: ...SDRAM Controller SDC 18 88 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 860: ...DMA Bus Debug Registers 20 30 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 908: ...SDRAM Controller External Bus Interface Unit B 36 ADSP BF535 Blackfin Processor Hardware Reference...