Freescale Semiconductor MPC5200B - Manual (Page 577)

MPC5200B Users Guide, Rev. 1
15-66 Freescale Semiconductor
PSC Operation Modes
Table 15-90. Signal Description for IrDa Mode
Figure 15-17. PSC SIR Block Diagram
15.3.4.1.2 Transmitting and Receiving in SIR Mode
This data format is similar to the UART. Each data consists of a start bit, 8 bit data and a stop bit. Each bit data is encoded so that a 0 is encoded
as 3/16 of the bit time pulse (or 1.6
µs pulse) and a 1 is encoded as no pulse. Similarly, the received serial pulse is decoded as a 0 and an
absence of a pulse is decoded as a 1. Like the UART mode, the SIR mode sends the lsb first. Here is an example of data stream of UART and
SIR.
Figure 15-18. Data Format in SIR Mode
NOTE
Please choose first the desired mode (SIR mode) than configure the port (write to port_config
register). This sequence will avoid pulses on the TX line during port configuration. This is very
important for all IrDA (SIR, MIR, and FIR) modes.
For more informations regarding the pulse width and Baud rate calculations see Section 15.2.25, Infrared SIR Divide Register (0x4C)—IRSDR
and Section 15.2.12, Counter Timer Upper Register (0x18)—CTUR.
Signal Description
IRDA_TX Transmitter Serial Data Output—Transfers must be specified as msb first.
IRDA_RX Receiver Serial Data Input—Transfers must be specified as msb first.
Receiver
Transmitter
Rx FIFO
Tx FIFO
Clock
Generation
Unit
IRDA_RX
IRDA_TX
External
Interface
Signals
IPB Clock
IPB
Interface
CommBus
Interface
IRQ
Controller
BestComm
Request
PSC
{CTUR:CTLR}
start
bit data bits(8 bit)
UART data
format
SIR data
format
0 1 0 1 0 1 1 0 0 1
stop
bit
3/16 of the bit width
or 1.6
µs
lsb msb