FIFO Interface
MPC5200B Users Guide, Rev. 1
Freescale Semiconductor 14-27
14.6 FIFO Interface
The programming interface to the FIFO allows access to Data, Status, Control, Last Write Pointer, Last Read Pointer, Alarm, Read and Write
Pointers for Transmit and Receive configurations. The FIFO can be accessed by byte, word, or longword, but all accesses must be aligned
with the most significant byte (big endian) of the data port. BestComm supports byte, word or longword accesses. The processor supports
longword access only. All register name access is longword aligned
.
Bits Name Description
0:28 — Reserved
28:31 X_WMRK Transmit FIFO Watermark—Frame transmission begins:
• If the number of bytes selected by this field are written into the transmit FIFO, or
• if an EOF is written to the FIFO, or
• if the FIFO is full before the selected number of bytes are written.
Options are:
0000 = 64Bytes written to FIFO.
0001 = 128Bytes written to FIFO.
0010 = 192Bytes written to FIFO.
0011 = 256Bytes written to FIFO.
0100 = 320Bytes written to FIFO.
0101 = 384Bytes written to FIFO.
0110 = 448Bytes written to FIFO.
0111 = 512Bytes written to FIFO.
1000 = 576Bytes written to FIFO.
1001 = 640Bytes written to FIFO.
1010 = 704Bytes written to FIFO.
1011 = 768Bytes written to FIFO.
1100 = 832Bytes written to FIFO.
1101 = 896Bytes written to FIFO.
1110 = 960Bytes written to FIFO.
1111 = 1024Bytes written to FIFO.

Table 14-30. FIFO Interface Register Map

Address byte0 byte1 byte2 by te3 Description
0x184 Data Data Data Data Receive FIFO Data
0x188 Stat Stat Receive FIFO Status
0x18C Ctl Receive FIFO Control
0x190 LRF LRF Receive Last Read Frame Pointer
0x194 LWF LWF Receive Last Write Frame Pointer
0x198 Alarm Alarm Receive (High/Low) Alarm Pointer
0x19C Read Read Receive FIFO Read Pointer
0x1A0 Write Write Receive FIFO Write Pointer
0x1A4 Data Data Data Data Transmit FIFO Data
0x1A8 Stat Stat Transmit FIFO Status
0x1AC Ctl Transmit FIFO Control
0x1B0 LRF LRF Transmit Last Read Frame Pointer