STE12PS datasheet(30/44 Pages) STMICROELECTRONICS

30 / 44 page

Obsolete

Product(s)

- Obsolete

Product(s)

I2C slave protocol overview

STE12PS

30/44

5.7

Parallel monitoring interface

In order to monitor the status of the different ports without the I2C register addressing, a

simple, output status interface has been implemented.

This digital interface is comprised of 9 output pins: CH_SEL[3:0], POK, OVLD, OVCUR,

AC_DC_DISCON and DET_CLASS.

Bits

CH_SEL[3:0] indicate the channel status flags (POK,..., DET_CLASS) that are currently

notified, externally. CH_SEL is incremented every 60MCLK clock cycles.

POK stands for Power OK. When HIGH, it indicates that the channel is currently powered-on

in normal condition.

OVLD stands for OverLoad and indicates a faulty condition due to abnormal power

dissipation (more than Pclass) of a powered channel.

OVCUR stands for OverCurrent, and it highlights a channel whose current has reached the

power-on current limit of 425mA (typ. value).

Bit

AC_DC_DISCON goes HIGH when a powered channel fails in providing a correct MPS

(maintain power signature). This typically happens when a PD is disconnected from the line.

DET_CLASS indicates a situation where a channel is not yet powered and whose

“signature” is currently being probed.

Status flag notification is enabled by bit STATUS_FLAG_EN of the configuration register

Global_cfg2. By default this bit is HIGH, that is, enabled.

This information is particularly useful in simple applications without a microprocessor or for

testing purposes. Another use is to easily build-up an LED graphical interface showing

runtime status of the various channels.

STE12PS 数据表(PDF) 30 Page - STMicroelectronics