Functional Descriptions

21644-DSH-001-B

Mindspeed Technologies

®

21

Mindspeed Proprietary and Confidential

4.1.2

Adaptive Equalizer

In typical hardware mode operation, the adaptive equalization is enabled with pin.MF0 = Low (bypass disabled).

However, with pin.MF0= High, the adaptive equalization and DC restore circuit are bypassed and the input is fed

directly to the output buffers.

In software mode operation, the equalizer block can be bypassed by setting register.GenConfig.bit[5] to 1b.

Once there is a signal detected at the input of the equalizer, the adaptive equalizer has the ability to report what

length of Belden 1694A cable is being used. The cable length indicator results can be read on registers 05h bit[0]

and register 06h bit[7:0]. The formulas to calculate the estimated cable length are:

CL(m) = 0.625*CLI, for 0-250 m

CL(m) = 2.5*(CLI - 400) + 250, for >250 m

where CLI is the decimal value of the 9 bits from registers 05h bit[0] (msb) and register 06h bit[7:0] (lsb) and CL is

the estimated Belden 1694A cable length in meters. Table 4-1 has some of the decoded values for the cable length

indicator registers.

Table 4-1.

Cable Length Indicator Decoder

CLI

Results

Estimated Cable Length*

000000000

0 m

000101000

25 m

001010000

50 m

001111000

75 m

010100000

100 m

011001000

125 m

011110000

150 m

100011000

175 m

101000000

200 m

101101000

225 m

110010000

250 m

110100100

300 m

110111000

350 m

111001100

400 m

111100000

450 m

* All cable length indicator values are approximate and are not guaranteed.