Freescale Semiconductor MPC5200B - Manual (Page 576)

PSC Operation Modes
MPC5200B Users Guide, Rev. 1
Freescale Semiconductor 15-65
the slot request for the specified slots was active (slot request bit was zero in the previous frame). If the AC97 Codec set a slot request to one,
then the transmitter will send a complete empty frame because the transmitter is not able to send a port of the required slots without changing
the order of the data in the FIFO.
If the software will send a command to the AC97 codec the “Control Register Index” and the “Control Register Write Data“ values must be
written to the
AC97CMD register. A write access to any word of this register will trigger the transmitter to send out the register value,
synchronous the SR [CMD_SEND] bit was set. The transmitter generate a slot0 tag which mark slot1 and slot2 as valid slot. If the receiver
was able to send out the command data, the SR [CMD_SEND] bit will be cleared.
If the receiver detect a valid data in time slot2, then the SR [DATA_VALID] bit was set by the receiver. The software can read the received
data from the AC97Data register, synchronous the read access to this register will clear the SR [DATA_VALID] bit. If the receive detect an
additional command data before the previous data was read out, the SR [DATA_OVR] bit was also set to one. The previous received command
data word goes lost. A read access tot the AC97Data register will clear the SR [DATA_VALID] and SR [DATA_OVR] register. Table 15-89
shows an example how to configure the AC97 controller. In this example the AC97 controller will only send time slot 3 and slot4 data and
will expect data for time slot9,10,11 and 12 on the receive site. For this purpose the software must write 2 data words to the TxFIFO for one
complete AC97 frame and must read 4 data words from the RxFIFO per frame.
Table 15-89. General Configuration Example for “enhanced” AC97 Mode
15.3.4 PSC in IrDA mode
The PSC support 3 different IrDA modes. These modes are described in the follows sections.
15.3.4.1 PSC in SIR Mode
The SIR mode is one of the supported IrDA modes. This section will give some more informations about this mode. The imported register to
configure the PSC6 (only this PSC support the IrDA modes) for SIR mode are:
• SICR register - select the SIR mode
• CTUR , CTLR register - select the Baud rate
• MR1 register - select the Receiver interrupt mode
• MR2 register - Channel Mode
• IRCR1 register - select the pulse width
• IRSDR register - select the counter for pulse width
• RFALARM , TFALARM - select the FIFO “Alarm” level
• CR register - enable or disable receiver and transmitter
• Port_config - select the right Pin-Muxing, see Chapter 2, Signal Descriptions
15.3.4.1.1 Block Diagram and Signal Definition for SIR Mode
The Table 15-90 shows the interface signal definition. This definition is equal for all IrDA modes. The Figure 15-17. shows the PSC in SIR
mode. The simplified block diagram describe the clock distribution.
Register Value Setting
CR 0x0A Disable the Tx and Rx part for configuration if the PSC was enabled by the work
before.
SICR 0x03010000 Select the enhanced AC97 mode
AC97Slots 0x0300000F define the expected receive and transmit slots
RFALARM 0x0XXX Choose Rx FIFO “almost full” threshold level.
TFALARM 0x0XXX Choose Tx FIFO “almost empty” threshold level.
IMR 0xXXXX select the desired interrupt
Port_Config 0x00000020 Select the Pin-Muxing for AC97 mode PSC2, see Chapter 2, Signal Descriptions
CR 0x05 Enable Tx and Rx