Marvell 88E3015 Manual page 81

Table 51: VCT™ Register for MDIP/N[0] Pins
Register 26
B i ts F i e l d
15 EnVCT
14:13 VCTTst
12:8 AmpRfln
7:0 DistRfln
Copyright © 2008 Marvell
January 4, 2008, Advance
M o d e H W S W
R s t R s t
R/W, 0x0 0x0
SC
RO 0x0 Retain
RO 0x00 Retain
RO 0x00 Retain
Document Classification: Proprietary Information
D e s c r i p t io n
Enable VCT
0 = VCT completed
1 = Run VCT
After running VCT once, bit 15 = 0 indicates VCT com-
pleted.
The cable status is reported in the VCTTst bits in regis-
ters 26 and 27.
Refer to the Virtual Cable Tester
VCT Test Status
These VCT test status bits are valid after completion of
VCT.
00 = Valid test, normal cable (no short or open in cable)
01 = Valid test, short in cable (Impedance < 33 ohm)
10 = Valid test, open in cable (Impedance > 333 ohm)
11 = Test fail
Amplitude of Reflection
The amplitude of reflection is stored in these register
bits. These amplitude bits range from 0x07 to 0x1F.
0x1F = Maximum positive amplitude
0x13 = Zero amplitude
0x07 = Maximum negative amplitude
These bits are valid after completion of VCT (bit 15) and
if the VCT test status bits (bits 14:13) have not indicated
test failure.
Distance of Reflection
These bits refer to the approximate distance (± 1m) to
the open/short location, measured at nominal conditions
(room temperature and typical VDDs)
These bits are valid after completion of VCT (bit 15) and
if the VCT test status bits (bit 14:13) have not indicated
test failure.
Doc. No. MV-S103657-00, Rev. D
Register Description
®
feature.
Page 81