Motorola MPC860 PowerQUICC User Manual page 728

Part V. The Communications Processor Module
MPC860
UART
(SCC2)
The signal between the UART and the encoder/decoder module is a bit stream of pulses in
a frame comprised of a start bit, 8 data bits, no parity bit, and ending with a stop bit, as
shown in Figure 26-10(a). The signal between the encoder/decoder module and infrared
(IR) transducer module is shown in Figure 26-10(b). The electrical pulses between the IR
transmit encoder and the output driver and LED are
the slower bit rates, as short as
between the detector, receiver, and IR receive decoder are nominally the same duration as
those between the IR transmit encoder, output driver, and LED.
Start
Bit
(a) 0
(b)
The SIR encoding/decoding is supported only for SCC2. To activate it, set GSMR_L2[SIR]
and conÞgure GSMR_L2[RDCR, TDCR] for 16x clock operation.
26-16
Encoder/Decoder
Module
TXD IR Transmit
Encoder
RXD IR Receive
Decoder
Figure 26-9. Serial Infrared (SIR) Link
3
/ of the bit period for 115.2 Kbps). Electrical pulses
16
UART Frame
1 0 1
Figure 26-10. UART and IR Frames
MPC860 PowerQUICC UserÕs Manual
IR Transducer
Module
Output Driver &
LED
Detector &
Receiver
3 / of a bit period in duration (or for
16
Data Bits
0 0 1
IR Frame
3/16 Bit Time
IR Out
IR In
Stop
Bit
1 0 1
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