MK50H25PLCC datasheet(35/64 Pages) STMICROELECTRONICS

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4.2.9 Error Counters Seven locations in the Initialization buffer are reserved for use as error counters

which the MK50H25 will increment. These counters are intended for use by the host CPU for statistical

analysis. The MK50H25 will only increment the counters; it is up to the user to clear and preset them.

The error counters are:

Memory Address

Error Counter

IADR + 44

Bad Frames Received

- Bad FCS

- Non-Octet Aligned

IADR + 46

Number of FRMR frames received.

IADR + 48

Number of T1 timeouts.

IADR + 50

Number of REJ frames received.

IADR + 52

Number of REJ frames transmitted.

IADR + 54

Frames shorter than minimum length received.

IADR + 56

Number of Aborted frames received. Enabled only if FCSER = 1

IADR + 58 thru IADR + 60

Reserved. Must be programmed as zeroes only if EIBEN = 1.

4.3 Receive and Transmit Descriptor Rings

Each descriptor ring in memory is a 4 word entry. The following is the format of the receive and transmit

descriptors.

4.3.1 Receive Message Descriptor Entry

4.3.1.1 Receive Message Descriptor 0 (RMD0)

BIT

NAME

DESCRIPTION

OWNA

When this bit is a zero either the HOST or the I/O ACCELERATION

PROCESSOR owns this descriptor.

When this bit is

one

the

MK50H25 owns this descriptor. The chip clears the OWNA bit af-

ter filling the buffer pointed to by the descriptor entry provided a valid

frame has been received. The Host sets the OWNA bit after emp-

tying the buffer.

Once the MK50H25,

Host, or I/O acceleration

processor has relinquished ownership of a buffer, it may not change

any field in the four words that comprise the descriptor entry.

OWNB

This bit determines whether the HOST or a Slave Processor or Process

owns the buffer when OWNA is a zero.

The MK50H25 never uses

this bit.

SLF

Start of Long Frame indicates that this is the first buffer used by the

MK50H25 for this frame. It is used for data chaining buffers. SLF is

set by the MK50H25.

NOTE: A ”Long Frame” is any frame which

needs chaining.

ELF

End of Long Frame indicates that this the last buffer used by MK50H25

for this frame. It is used for data chaining buffers. If both SLF and ELF

were set, the frame would fit into one buffer and no data chaining

would be required. ELF is set by the MK50H25.

RBADR<23:16>

MK50H25

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