37 rx fifo last write frame ptr (0x7c)-rflwfptr, 38 tx fifo data (0x80)-tfdata, 39 tx fifo status (0x84)-tfstat – Freescale Semiconductor MPC5200B User Manual

Page 552: Rx fifo last write frame ptr (0x7c)—rflwfptr -36, Tx fifo data (0x80)—tfdata -36, Tx fifo status (0x84)—tfstat -36, Rx fifo last write frame ptr (0x7c) -36, Tx fifo stat (0x84) -36, Rx fifo last write frame ptr (0x7c)—rflwfptr, Tx fifo data (0x80)—tfdata

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PSC Registers—MBAR + 0x2000, 0x2200, 0x2400, 0x2600, 0x2800, 0x2C00

MPC5200B Users Guide, Rev. 1

Freescale Semiconductor

15-41

15.2.37

Rx FIFO Last Write Frame PTR (0x7C)—RFLWFPTR

15.2.38

Tx FIFO Data (0x80)—TFDATA

Read - write register to access the internal TX FIFO Data register. Write to this register write data to the transmit FIFO. Additional the register
provide the possibility to read data back from the TX FIFO for debug issues. For more informations about the data format see

Section 15.2.7,

Tx Buffer Register (0x0C)—TB.

15.2.39

Tx FIFO Status (0x84)—TFSTAT

For additional informations about the FIFO related status bits see

Section 15.2.3, Status Register (0x04) — SR.

NOTE

To make sure that the PSC never lost the data in the FIFO, the PSC controller avoid writing to a full
FIFO or reading from an empty FIFO. Therefore the status bits in the FIFO STAT register never
reports an ERROR, UF or OF state. The

SR

register reports these errors.

Table 15-65. Rx FIFO Last Write Frame PTR (0x7C)

msb 0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15 lsb

R

Reserved

LFP

W

RESET:

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

Name

Description

0:3

Reserved

4:15

LFP

Last Frame Pointer. Not applicable to PSC FIFOs, since the PSCs do not recognize frame
formats in the serial data stream.

Table 15-66. Tx FIFO STAT (0x84)

msb 0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15 lsb

R

Reserved

F

rame[

3

]

F

rame[

2

]

F

rame[

1

]

F

rame[

0

]

Rese

rved

Error

UF

OF

FR

FULL

ALARM

EMPTY

W

RESET:

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Bit

Name

Description

0:3

Reserved

4:7

Frame[3:0]

Frame indicator. Not applicable to PSC FIFOs, since the PSCs do not recognize frame
formats in the serial data stream.

8

Reserved

9

Error

FIFO error. A FIFO error has occurred due to either underflow, overflow, or read or write
pointer out of bounds.This bit is cleared by writing 1 to it.

10

UF

Underflow. The read pointer has surpassed the write pointer due to the FIFO having been
read when it contained no data. This bit is cleared by writing 1 to it.

11

OF

Overflow. The write pointer has surpassed the read pointer due to the FIFO having been
written when it was already completely full of data. This bit is cleared by writing 1 to it.

12

FR

Frame ready. Not applicable to PSC FIFOs, since the PSCs do not recognize frame formats
in the serial data stream.

13

FULL

Full. The FIFO is completely full of data.

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