SI3452MS8-EVB Silicon Laboratories Inc, SI3452MS8-EVB Datasheet - Page 12

• Manufacturer Part Number: SI3452MS8-EVB
• Manufacturer: Silicon Laboratories Inc

Specifications of SI3452MS8-EVB

• Lead Free Status / Rohs Status: Supplier Unconfirmed

Si3452MS8-EVB
G. Clicking the reset button results in the reset command being written to register 0x12. This results in a complete
H. Clicking the Midspan mode button results in sending the command to register 0x12 that toggled the detection
I. The boxes in this pane set the more advanced port configuration bits in the port configuration registers. A port
J. This pane displays the event register information. The port event registers are clear on read; so, clicking the
K. The device status register read in this pane. The device status register is not clear on read; but, when it is read,
L. These panes display the contents of the port current registers. These registers are 2 bytes; so, to make sure the
M. The interrupt pin status and interrupt pin mask are displayed in this pane. The USB to SMBus adapter does not
N. The Si3452 revision registers and Vee information is displayed in this pane. Vee is a 2-byte register; so, Vee is
O. The button in this pane issues the "turn off low priority ports" command. This command is always sent to the
12
GUI Display
Detect
Class
Mode drop down
menu
Turn on or Turn off Depending on whether the port is on or off (as determined by the Penable bit 6 of the port
reset of the Si3452 that is being addressed.
back-off delay time from end point mode to mid-span mode.
that is "low priority" will be turned off when the "turn off low priority ports" is written. Normally, when the PD is
removed, it will be disconnected; but, if the disconnect enable bit is not checked, the port will stay on until forced
off by a command. 2x power mode doubles the port current limiting to approximately 850 mA and enables
2-event classification. If Icut is exceeded for 60 msec, the port will also be turned off. In auto mode, Icut is set
according to the port classification and 2x power mode, but it can be changed dynamically.
read button displays the contents and then clears the register.
this clears bits 5 and 6 of the interrupt register if they are set. The device status register is polled; so, in polling
mode, device status events only generate a momentary interrupt.
bytes are synchronized, there is a command that is sent to Register x012 to read the current. The read current
command is sent by clicking the button in this pane. In polling mode, the current is read and updated as part of
the polling process.
continuously monitor the interrupt pin; so, there is some delay between pin transitions and display of the pin
status on the GUI.
read by issuing a command in polling mode. Since the GUI does not have a button for issuing the read Vee
command, click the "Refresh" button in pane E to update the Vee information.
broadcast address (0x30); so, clicking this button results in all low-priority ports on both devices being turned
off.
The lower three bits of the port status registers are the detection status bits. These bits are
decoded and displayed as the detect status. Detection status indicates the result of powered
device (PD) detection. If a detection has not been done, the result is “unknown”. Other possi-
ble results are “short circuit”, “resistance too low”, “valid or good detection result”, “resistance
too high”, or “open circuit”.
The next three bits are classification status. If a classification has not been done, the result is
“unknown”; otherwise, the PD classification is shown (class 0 – 4); this is displayed if there
was an error due to overload or unequal events for the PoE+ two-event classification.
The lower two bits of the port mode register can be set by the drop-down menu. The possible
modes are “shutdown” (port cannot be turned on), “manual” (port can be turned on by send-
ing a turn on command), “semi-auto” (detection is performed, and, if the result is “good”,
classification is performed; the port can be turned on by sending a turn on command), and
“auto” (detection, classification, and port turn-on are all automatic).
status register), the turn on port or turn off port command button is presented. Clicking this
button results in the appropriate command being written to register 0x12.
Table 2.
Rev. 0.4
Description