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Description of Operation
13-12
ADSP-BF537 Blackfin Processor Hardware Reference
For legacy reasons, the
UARTx_IIR
registers still reflect the UART interrupt
status. Legacy operation may require bundling all UART interrupt sources
to a single interrupt channel and servicing them all by the same software
routine. This can be established by globally assigning all UART interrupts
to the same interrupt priority, by using the System Interrupt Controller
(SIC).
L
If either the line status interrupt or the receive data interrupt has
been assigned a lower interrupt priority by the SIC, a deadlock
condition can occur. To avoid this, always assign the lowest prior-
ity of the enabled UART interrupts to the
UARTx_THR
empty event.
Bit Rate Generation
The UART clock is enabled by the
UCEN
bit in the
UARTx_GCTL
register.
The bit rate is characterized by the system clock (
SCLK
) and the 16-bit
divisor. The divisor is split into the
UARTx_DLL
and the
UARTx_DLH
regis-
ters. These registers form a 16-bit divisor. The bit clock is divided by 16
so that:
BIT RATE = SCLK/(16 x Divisor)
Divisor = 65,536
when
UARTx_DLL = UARTx_DLH = 0
provides example divide factors required to support most stan-
dard baud rates.
Table 13-1. UART Bit Rate Examples With 100 MHz SCLK
Bit Rate
DL
Actual
% Error
2400
2604
2400.15
.006
4800
1302
4800.31
.007
9600
651
9600.61
.006
19200
326
19171.78
.147
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 ...
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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 ...