ADSP-BF50x Blackfin Processor Hardware Reference
15-9
UART Port Controllers
If enabled by the
ERBFI
bit in the
UARTx_IER
register, the
DR
flag requests
an interrupt on the dedicated
RXREQ
output. This signal is routed through
the DMA controller. If the associated DMA channel is enabled, the
RXREQ
signal functions as a DMA request, otherwise the DMA controller 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 redirect the
receive and transmit interrupts to the UART status interrupt alternatively.
The state of the five-deep receiver buffer (including
UARTx_RBR
) can be
monitored by the receiver FIFO count status (
RFCS
) bit in the
UARTx_MSR
register. The buffer’s behavior is controlled by the receive FIFO interrupt
threshold (
RFIT
) bit in the
UARTx_MCR
register. If
RFIT
is zero, the
RFCS
bit
is set when the receive buffer holds two or more words. If
RFIT
is set, the
RFCS
bit is set when the receive buffer holds four or more words. The
RFCS
bit is cleared by hardware when core or DMA read the
UARTx_RBR
register
and when the buffer is flushed below the level of two (
RFIT
=0) or four
(
RFIT
=4). If the associated interrupt bit
ERFCI
is enabled, status interrupt
is reported when the
RFCS
bit is set.
If errors are detected during reception, an interrupt can be requested to a
the status interrupt output. This status interrupt request goes directly to
the SIC interrupt controller. Status interrupt requests are enabled by the
ELSI
bit in the
UARTx_IER_SET
register. The following error situations are
detected. Every error has an indicating bit in the
UARTx_LSR
register.
• Overrun error (
OE
bit)
• Parity error (
PE
bit)
• Framing error/Invalid stop bit (
FE
bit)
• Break indicator (
BI
bit)
The sampling clock is 16 times faster than the bit clock. The receiver over
samples every bit 16 times and does a majority decision based on the mid
three samples. This improves immunity against noise and hazards on the
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 ...