ADSP-BF50x Blackfin Processor Hardware Reference
15-29
UART Port Controllers
The
STB
bit controls how many stop bits are appended to transmitted
data. When
STB=0
, one stop bit is transmitted. If
WLS
is non zero,
STB=1
instructs the transmitter to add one additional stop bit, two stop bits in
total. If
WLS=0
and 5-bit operation is chosen,
STB=1
forces the transmitter
to append one additional half bit, 1 1/2 stop bits in total. Note that this
bit does not impact data reception—the receiver is always satisfied with
one stop bit.
The
PEN
bit inserts one additional bit between the most significant data bit
and the first stop bit. The polarity of this so-called parity bit depends on
data and the
STP
and
EPS
control bits. Both transmitter and receiver calcu-
late the parity value. The receiver compares the received parity bit with
the expected value and issues a parity error if they don’t match. If
PEN
is
cleared, the
STP
and the
EPS
bits are ignored.
The
STP
bit controls whether the parity is generated by hardware based on
the data bits or whether it is set to a fixed value. If
STP=0
the hardware cal-
culates the parity bit value based on the data bits. Then, the
EPS
bit
determines whether odd or even parity mode is chosen. If
EPS=0
, odd par-
ity is used. That means that the total count of
logical–1
data bits
including the parity bit must be an odd value. Even parity is chosen by
STP=0
and
EPS=1
. Then, the count of
logical–1
bits must be a even value.
If the
STP
bit is set, then hardware parity calculation is disabled. In this
case, the sent and received parity equals the inverted
EPS
bit. The example
in
Table 15-5
summarizes polarity behavior assuming 8-bit data words
(
WLS=3
).
Table 15-5. UART Parity
PEN
STP
EPS
Data (hex)
Data (binary, LSB
first)
Parity
0
x
x
x
x
None
1
0
0
0x60
0000 0110
1
1
0
0
0x57
1110 1010
0
1
0
1
0x60
0000 0110
0
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 ...