Incor User's Guide Ethernet Media Access Controller TMS320C645x DSP

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5.39 Back Off Test Register (BOFFTEST)
EMAC Port Registers
The back off test register (BOFFTEST) is shown in Figure 67 and described in Table 67 .
Figure 67. Back Off Random Number Generator Test Register (BOFFTEST)
31 26 25 16
Reserved RNDNUM
R-0 R-0
15 12 11 10 9 0
COLLCOUNT Reserved TXBACKOFF
R-0 R-0 R-0
LEGEND: R = Read only; - n = value after reset
Table 67. Back Off Test Register (BOFFTEST) Field Descriptions
Bit Field Value Description
31-26 Reserved 0 Reserved
25-16 RNDNUM Back off random number generator. This field allows the Back off Random Number Generator to be
read. Reading this field returns the generator's current value. The value is reset to zero and begins
counting on the clock after the de-assertion of reset.
15-12 COLLCOUNT Collision count. These bits indicate the number of collisions the current frame has experienced.
11-10 Reserved 0 Reserved
9-0 TXBACKOFF Back off count. This field allows the current value of the back off counter to be observed for test
purposes. This field is loaded automatically according to the back off algorithm, and is decremented
by one for each slot time after the collision.
SPRU975B – August 2006 Ethernet Media Access Controller (EMAC)/Management Data Input/Output (MDIO) 125
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