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DS00002838B-page 21

UPD301A

If supported, the ranges 8V, 12V and 20V may be programmed in VBUS Threshold 2 and VBUS Threshold 3 registers.

Likewise 5V range, vSafe5v, can be programmed in VBUS Threshold 0 and VBUS Threshold 1 registers.

The threshold for vSafe0V is programmable.

VBUS_DET_IN monitoring logic operates off of the 20 KHz oscillator which cycles through each threshold. Including

vSafe0v, a total of five values are compared.

4.4

Baseband CC Interface (BCI)

The device integrates a Baseband CC Interface (BCI) to facilitate USB Power Delivery communication. This module

bridges between the PD MAC/BMC and the analog front end. Baseband communication is initiated by the PD MAC,

which interfaces to the BCI. The BCI implements the digital functions required to control TX baseband components.

4.4.1

BASEBAND TX DATA-FLOW

The key responsibility of the BCI is to generate the wave form required for baseband communication. To this end, the

BMC has a group of eight registers that define the Lo-Hi and Hi-Lo transitions for the generated BMC signal.

When instructed to transition from Lo-Hi, the BCI steps through all BB TX Rise Registers. Likewise when instructed to

transition from Hi-Lo, the BCI steps through all BB TX Fall Registers

APPLICATION NOTE:

The user may replicate values if it is desired to use less than twelve unique values for this

purpose.

4.4.2

BASEBAND RX DATA-FLOW

Baseband RX data is received by the BCI from the RX analog front end where it is compared to a threshold programmed

by software. The CC RX DAC Value defines the trip point used for reception of baseband data. The field shall be pro-

grammed to be 175 mV below the RX Eye center, as defined in the PD Specification for the mode in which the device

is operating (Sourcing Power, Sinking Power, Power Neutral).

TABLE 4-5:

VBUS DETECTION THRESHOLDS

VBUS

Range

VBUS_DET_IN

Comments

20

21.5

2.11

18.5

1.82

12

13.1

1.29

10.9

1.07

8

8.9

0.88

7.1

0.69

5

5.5

0.51

vSafe5V

3.67

0.33

0.68

0.68

0.068

vSafe0V