ADSP-BF537 Blackfin Processor Hardware Reference
13-5
UART Port Controllers
Using the 16x data rate clock, RZI modulation is achieved by inverting
and modulating the non-return-to-zero (NRZ) code normally transmitted
by the UART. On the receive side, the 16x clock is used to determine an
IrDA pulse sample window, from which the RZI-modulated NRZ code is
recovered.
IrDA support is enabled by setting the
IREN
bit in the
UARTx_GCTL
register.
The IrDA application requires external transceivers.
UART Transmit Operation
Receive and transmit paths operate completely independently except that
the bit rate and the frame format are identical for both transfer directions.
Transmission is initiated by writes to the
UARTx_THR
register. If no former
operation is pending, the data is immediately passed from the
UARTx_THR
register to the internal
TSR
register where it is shifted out at a bit rate equal
to
SCLK/(16 × Divisor)
with start, stop, and parity bits appended as
defined the
UARTx_LCR
register. The least significant bit (LSB) is always
transmitted first. This is bit 0 of the value written to
UARTx_THR
.
Writes to the
UARTx_THR
register clear the
THRE
flag. Transfers of data from
UARTx_THR
to the transmit shift registers (
TSR
) set this status flag in
UARTx_LSR
again.
Figure 13-2. Bitstream on a TX Pin Transmitting an “S” Character (0x53)
DATA BITS
STOP BIT(S)
START BIT
LSB
PARITY BIT (OPTIONAL, ODD OR EVEN)
D0
D1
D2
D3
D4
D5
D6
D7
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 ...