ADSP-BF535 Blackfin Processor Hardware Reference
11-19
Serial Port Controllers
SPORTx Receive (SPORTx_RX) Registers
The
SPORTx_RX
register, shown in
Figure 11-6
, acts as the receive data
buffer for the SPORT. It is a 16-bit register which is automatically loaded
from the receive shifter when a complete word has been received. Word
lengths of less than 16 bits are right justified.
The SPORT receive registers act like a two-location FIFO buffer because
there is a data register (
SPORTx_RX
) with an accompanying input shift reg-
ister as shown in
Figure 11-1 on page 11-5
. Two 16-bit words may be
stored in these registers at any one time.
SPORTx_RX
is read-only and the
reset values are undefined.
Two 16-bit words can be stored in the SPORT receive registers at any one
time. The third word overwrites the second if the first word has not been
read out by the Master core or the DMA controller. When this happens,
the receive overflow status bit (
ROVF
) is set in the SPORT Status register.
The overflow status is generated on the last bit of the second word. The
ROVF
status bit is sticky and is only cleared by disabling the serial port.
An interrupt is generated when the
SPORTx_RX
register has been loaded
with a received word (that is, the
SPORTx_RX
register is not empty). This
interrupt is masked out if serial port DMA is enabled.
If the program causes the core processor to attempt a read from an empty
SPORTx_RX
register, any old data is read. If it is not known whether the
core processor can access the
SPORTx_RX
register without causing such an
error, the register’s full or empty status should be read first (in the SPORT
Status register) to determine if the access can be made.
Table 11-4. SPORTx Transmit Register MMR Assignments
Register Name
Memory-Mapped Address
SPORT0_TX
0xFFC0 2804
SPORT1_TX
0xFFC0 2C04
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...