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
Summary of Contents for Blackfin ADSP-BF537
Page 42: ...Contents xlii ADSP BF537 Blackfin Processor Hardware Reference ...
Page 90: ...Development Tools 1 32 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 138: ...Programming Examples 4 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 340: ...SDC Programming Examples 6 84 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 606: ...Programming Examples 9 94 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 660: ...Programming Examples 10 54 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 720: ...Electrical Specifications 11 60 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 840: ...Programming Examples 13 42 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 876: ...Programming Examples 14 36 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 938: ...Programming Examples 15 62 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 958: ...Programming Examples 17 12 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 986: ...Programming Examples 18 28 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 1162: ...G 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 1218: ...Index I 56 ADSP BF537 Blackfin Processor Hardware Reference ...