Description of Operation
10-22
ADSP-BF537 Blackfin Processor Hardware Reference
When
SPE
and
MSTR
are cleared, the SPI data and clock pin drivers (
MOSI
,
MISO
, and
SCK
) are disabled. However, the slave select output pins revert to
being controlled by the general-purpose I/O port registers. This could lead
to contention on the slave select lines if these lines are still driven by the
processor. To ensure that the slave select output drivers are disabled once
an
MODF
error occurs, the program must configure the general-purpose I/O
port registers appropriately.
When enabling the
MODF
feature, the program must configure as inputs all
of the port pins that will be used as slave selects. Programs can do this by
configuring the direction of the port pins prior to configuring the SPI.
This ensures that, once the
MODF
error occurs and the slave selects are auto-
matically reconfigured as port pins, the slave select output drivers are
disabled.
Transmission Error (TXE)
The
TXE
bit is set in
SPI_STAT
when all the conditions of transmission are
met, and there is no new data in
SPI_TDBR
(
SPI_TDBR
is empty). In this
case, the contents of the transmission depend on the state of the
SZ
bit in
SPI_CTL
. The
TXE
bit is sticky (W1C).
Reception Error (RBSY)
The
RBSY
flag is set in the
SPI_STAT
register when a new transfer is com-
pleted, but before the previous data can be read from
SPI_RDBR
. The state
of the
GM
bit in the
SPI_CTL
register determines whether
SPI_RDBR
is
updated with the newly received data. The
RBSY
bit is sticky (W1C).
Transmit Collision Error (TXCOL)
The
TXCOL
flag is set in
SPI_STAT
when a write to
SPI_TDBR
coincides with
the load of the shift register. The write to
SPI_TDBR
can be via software or
the DMA. The
TXCOL
bit indicates that corrupt data may have been loaded
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 ...