AX88796BLF datasheet(23/82 Pages) ASIX

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ASIX ELECTRONICS CORPORATION

AX88796BLF / AX88796BLI

4.2.5 Other Useful Operations

Memory Diagnostics

Memory diagnostics can be achieved by Remote Write/Read DMA operations. The following is a suggested step for

memory test and assume the AX88796B has been well initialized.

Issue the STOP command to the AX88796B. This is accomplished be setting the STP bit in the AX88796B's

Command Register. Writing 21H to the Command Register will stop the AX88796B.

Wait for at least 1.5 ms. Since the AX88796B will complete any reception that is in progress, it is necessary

to time out for the maximum possible duration of an Ethernet reception. This action prevents buffer memory

from written data through Local DMA Write.

Write data pattern to MUT (memory under test) by Remote DMA write operation.

Read data pattern from MUT (memory under test) by Remote DMA read operation.

Compare the read data pattern with original write data pattern and check if it is equal.

Repeat step 3 to step 5 with various data pattern.

Loop-back Diagnostics

Issue the STOP command to the AX88796B. This is accomplished be setting the STP bit in the AX88796B's

Command Register. Writing 21h to the Command Register will stop the AX88796B.

Wait for at least 1.5 ms. Since the AX88796B will complete any reception that is in progress, it is necessary

to time out for the maximum possible duration of an Ethernet reception. This action prevents buffer memory

from written data through Local DMA Write.

Place the AX88796B in mode 1 loop-back. (MAC internal loop-back) This can be accomplished by setting

LB1 and LB0, of the Transmit Configuration Register to ``0,1''.

Issue the START command to the AX88796B. This can be accomplished by writing 22h to the Command

Write data that want to transmit to transmit buffer by Remote DMA write operation.

Issue the TXP command to the AX88796B. This can be accomplished by writing 26h to the Command

Read data current receive buffer by Remote DMA read operation.

Compare the received data with original transmit data and check if it is equal.

Repeat step 5 to step 8 for more packets test.

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