ADSP-BF535 Blackfin Processor Hardware Reference
12-5
UART Port Controller
The Break Interrupt (
BI
), Overrun Error (
OE
), Parity Error (
PE
) and Fram-
ing Error (
FE
) bits are cleared when the UART Line Status register
(
UARTx_LSR
) is read. The Data Ready (
DR
) bit is cleared when the UART
Receive Buffer register (
UARTx_RBR
) is read. Because of the destructive
nature of these read operations, special care should be taken. See
“Specula-
tive Load Execution” on page 6-81
and
“Conditional Load Behavior” on
page 6-82
for more information.
UARTx Transmit Holding Registers (UARTx_THR)
A write to the UARTx Transmit Holding register (
UARTx_THR
), shown in
Figure 12-4
, initiates the transmit operation. The data is moved to the
internal Transmit Shift register (
TSR
) where it is shifted out at a baud rate
equal to
SCLK/(16
Divisor
) with start, stop, and parity bits appended as
required. All data words begin with a 1-to-0-transition start bit. The
transfer of data from
UARTx_THR
to the Transmit Shift register sets the
Transmit Holding Register Empty (
THRE
) status flag in the UARTx Line
Status register (
UARTx_LSR
).
The
UARTx_THR
register is mapped to the same address as
UARTx_RBR
and
UARTx_DLL
. To access
UARTx_THR
, the
DLAB
bit in
UARTx_LCR
must be
cleared. When the
DLAB
bit is cleared, writes to this address target the
UARTx_THR
register, and reads from this address return the
UARTx_RBR
register.
Note that data is transmitted and received least significant bit first (bit 0)
followed by the most significant bits.
Figure 12-4. UARTx Transmit Holding Registers
Transmit Hold[7:0]
7
6
5
4
3
2
1
0
0
0
0
0
0
0
Reset = 0x00
0
0
UARTx Transmit Holding Registers (UARTx_THR)
WO
For MMR assignments,
see
Table 12-3
.
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...