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UART Registers
13-22
ADSP-BF537 Blackfin Processor Hardware Reference
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
summarizes polarity behavior assuming 8-bit data words
(
WLS=3
).
Table 13-3. UART Priority
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
1
0
1
0x57
1110 1010
1
1
1
0
x
x
1
1
1
0
x
x
1
1
1
1
x
x
0
1
1
1
x
x
0
Содержание Blackfin ADSP-BF537
Страница 42: ...Contents xlii ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 90: ...Development Tools 1 32 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 138: ...Programming Examples 4 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 340: ...SDC Programming Examples 6 84 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 606: ...Programming Examples 9 94 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 660: ...Programming Examples 10 54 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 720: ...Electrical Specifications 11 60 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 840: ...Programming Examples 13 42 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 876: ...Programming Examples 14 36 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 938: ...Programming Examples 15 62 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 958: ...Programming Examples 17 12 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 986: ...Programming Examples 18 28 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 1162: ...G 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 1218: ...Index I 56 ADSP BF537 Blackfin Processor Hardware Reference ...