MPC5200B Users Guide, Rev. 1
15-42 Freescale Semiconductor
PSC Registers—MBAR + 0x2000, 0x2200, 0x2400, 0x2600, 0x2800, 0x2C00
15.2.40 Tx FIFO Control (0x88)—TFCNTL15.2.41 Tx FIFO Alarm (0x8E)—TFALARM15.2.42 Tx FIFO Read Pointer (0x92)—TFRPTR
14 ALARM The FIFO is requesting service from eith er BestComm or CPU. See Section 15.4, PSC FIFO
System for a detailed description.
15 EMPTY FIFO Empty. The FIFO is completely empty.

Table15-67. Tx FIFO Control (0x88)

msb 0 1 2 3 4 5 6 7 lsb
RReserved WFR COMP FRAME GR[2:0]
W
RESET: 0 0001001
Bit Name Description
0:1 — Reserved
2 WFR Write frame. Not applicable for PSC FIFOs, since the PSCs do not recognize frame formats in
the serial data stream.
3 COMP Re-enable requests on frame transmission completion. Not applicable to PSC FIFO’s, since
the PSCs do not recognize frame formats in the serial data stream.
4 FRAME Frame mode enable. THIS BIT MUST BE CLEARED BY WRITING A ‘0’ TO IT, since the PSCs
do not recognize frame formats in the serial data stream.
5:7 GR [2: 0] Last transfer granularity. Four times this value is the amount of data remaining in the FIFO at
which the ALARM bit in the status register will go low/inactive. See Section 15.4, PSC FIFO
System for details.

Table15-68. Tx FIFO Alarm (0x8E)

msb 012345678 9 101112131415 lsb
RReserved ALARM
W
RESET:000000000 1 1 111 1 1
Bit Name Description
0:3 — Reserved
4:15 ALARM “Almost empty” threshold level. Amount of data remaining in the Tx FIFO at which the ALARM
bit in the status register goes high/active. See Section 15.4, PSC FIFO System for details

Table15-69. Tx FIFO Read Pointer (0x92)

msb 012345678 9 101112131415 lsb
RReserved R_PTR
W
RESET:000000000 0 0 000 0 0
Bit Name Description