ADSP-BF50x Blackfin Processor Hardware Reference
15-13
UART Port Controllers
IrDA Transmit Operation
To generate the IrDA pulse transmitted by the UART, the normal NRZ
output of the transmitter is first inverted if the
TPOLC
bit is cleared, so a 0
is transmitted as a high pulse of 16 UART clock periods and a 1 is trans-
mitted as a low pulse for 16 UART clock periods. The leading edge of the
pulse is then delayed by six UART clock periods. Similarly, the trailing
edge of the pulse is truncated by eight UART clock periods. This results in
the final representation of the original 0 as a high pulse of only 3/16 clock
periods in a 16-cycle UART clock period. The pulse is centered around
the middle of the bit time, as shown in
Figure 15-4
. The final IrDA pulse
is fed to the off-chip infrared driver.
This modulation approach ensures a pulse width output from the UART
of three cycles high out of every 16 UART clock cycles. As shown in
Table 15-2 on page 15-19
, the error terms associated with the bit rate gen-
erator are very small and well within the tolerance of most infrared
transceiver specifications.
Figure 15-4. IrDA Transmit Pulse
0
1
0
8/16
9/16
7/16
16/16
NRZ
INVERTED
FINAL
IrDA
8/16
9/16
7/16
16/16
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 ...