UART Registers
15-26
ADSP-BF50x Blackfin Processor Hardware Reference
the interrupt occurs, software can write new data into the
UARTx_THR
regis-
ter as soon as the
THRE
bit permits. If the
SYNC
bit cannot be set, software
can poll the
DMA_RUN
bit instead.
When switching from non-DMA to DMA operation, take care that the
very first DMA request is issued properly. If the DMA is enabled while the
UART is still transmitting, no precaution is required. If, however, the
DMA is enabled after the
TEMT
bit became high, the
ETBEI
bit should be
pulsed to initiate DMA transmission.
UART Registers
The processor provides a set of PC-style industry-standard control and
status registers for each UART. These memory-mapped registers (MMRs)
are byte-wide registers that are mapped as half words with the most signif-
icant byte zero filled.
Table 15-3
provides an overview of the UART
registers.
Unlike on ADSP-BF52x processors, register addresses are not shared on
ADSP-BF50x processors. Each register has its own MMR address. Conse-
quently, the
DLAB
bit is not present on ADSP-BF50x processors’
UARTx_
LSR
registers. Software must use 16-bit word load/store instructions to
access these registers.
Furthermore, the interrupt processing differs from ADSP-BF52x proces-
sors. Error bits in status registers do not clear on register reads implicitly,
rather they are cleared by write-1-to-clear (W1C) operations. The
UARTx_
IIR
register is not present at all. The interrupt enable register has separate
set and clear ports, so that separate receive, transmit, and status interrupt
service routines can enable or set masks individually.
Transmit and receive channels are both buffered. The
UARTx_THR
registers
buffer the transmit shift registers (
TSR
). The
UARTx_RBR
registers and an
Summary of Contents for EZ-KIT Lite ADSP-BF506F
Page 50: ...Contents l ADSP BF50x Blackfin Processor Hardware Reference ...
Page 92: ...Development Tools 1 30 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 110: ...Interface Overview 3 12 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 236: ...Internal Flash Memory Control Registers 6 92 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 650: ...Programming Examples 15 56 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 804: ...Programming Examples 17 92 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 1194: ...Programming Examples 24 90 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 1256: ...ACM Registers A 50 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 1264: ...Boundary Scan Architecture B 8 ADSP BF50x Blackfin Processor Hardware Reference ...