ADSP-BF50x Blackfin Processor Hardware Reference
15-7
UART Port Controllers
IrDA support is enabled by setting the
IREN
bit in the
UARTx_GCTL
register.
The IrDA application requires external transceivers.
UART Transmit Operation
Receive and transmit paths operate completely independently except that
the bit rate and the frame format are identical for both transfer directions.
Transmission is initiated by writes to the UARTx_THR register. If no for-
mer operation is pending, the data is immediately passed from the
UARTx_THR register to the internal TSR register where it is shifted out
at a bit rate characterized by the formula that follows with start, stop, and
parity bits appended as defined by the UARTx_LCR register:
The least significant bit (LSB) is always transmitted first. This is bit 0 of
the value written to
UARTx_THR
.
Writes to the
UARTx_THR
register clear the
THRE
flag. Transfers of data from
UARTx_THR
to the transmit shift registers (
TSR
) set this status flag in
UARTx_
LSR
again.
When enabled by the
ETBEI
bit in the
UARTx_IER
register, the
THRE
flag
requests an interrupt on the dedicated
TXREQ
output. This signal is routed
through the DMA controller. If the associated DMA channel is enabled,
the
TXREQ
signal functions as a DMA request, otherwise the DMA control-
ler simply forwards it to the SIC interrupt controller. If no DMA channel
is assigned to the UART, the
EGLSI
bit in the
UARTx_GCTL
register can redi-
rect the receive and transmit interrupts to the UART status interrupt
alternatively.
The
UARTx_THR
register and the internal
TSR
register can be seen as a
two-stage transmit buffer. When data is pending in either one of these reg-
isters, the
TEMT
flag is low. As soon as all data has left the
TSR
register, the
BIT RATE
SCLK
16
1
EDB0
–
Divisor
-----------------------------------------------------
=
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 ...