Maxim DS33R11 Registers Related to Setting the Ethernet Port, Register Name Function

DS33R11 Ethernet Mapper with Integrated T1/E1/J1 Transceiver

The MAC circuitry generates a frame status for every frame that is received. This real time status can be read by SU.RFSB0 to SU.RFSB3. Note the frame status is the “real time” status and hence the value will change as new frames are received. Hence the real time status reflects the status in time and may not correspond to the current received frame being processed. This is also true for the transmitted frames.

Frames with errors are usually rejected by the DS33R11. The user has the option of accepting frames by settings in Receive Frame Rejection Control register (SU.RFRC). The user can program whether to reject or accept frames with the following errors:

•MII error asserted during the reception of the frame

•Dribbling bits occurred in the frame

•CRC error occurred

•Length error occurred—the length indicated by the frame length is inconsistent with the number of bytes received

•Control frame was received. The mode must be full duplex

•Unsupported control frame was received

Note that frames received that are runt frames or frames with collision will automatically be rejected.

Table 9-5. Registers Related to Setting the Ethernet Port

REGISTER	NAME	FUNCTION
Transmit Frame Resend	SU.TFRC	This register determines if the current frame is retransmitted
Control		due to various transmit errors.
Transmit Frame Status Low	SU.TFSL and	These two registers provide the real-time status of the
and Transmit Frame Status
	SU.TFSH	transmit frame. Only apply to the last frame transmitted.
High
Receive Frame Status Byte 0	SU.RFSB0 to 3	These registers provide the real-time status for the received
to 3		frame. Only apply to the last frame received.
Receive Frame Rejection	SU.RFRC	This register provides settings for reception or rejection of
Control		frame based on errors detected by the MAC.
Receiver Maximum Frame	SU.RMFSRH and	The settings for this register provide the maximum size of
High and Receiver Maximum
	SU.RMFSRL	frames to be accepted from the MII/RMII receive interface.
Frame Low
MAC Control	SU.MACCR	This register provides configuration control for the MAC.

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