SLVSF02D March 2019 – May 2020 TPS23881
COMMAND = 28h with 1 Data Byte, Read/Write
|LEGEND: R/W = Read/Write; R = Read only; -n = value after reset|
|7–0||MBPn_2-0||R/W||0||MBPn_2-0: Multi Bit Priority bits, three bits per channel, if 3-bit shutdown priority has been selected (MbitPrty in General Mask register is high). It is used to determine which channel(s) is (are) shut down in response to a serial shutdown code received at the OSS shutdown input.
The turn off procedure (including register bits clearing) is similar to a channel reset using Reset command (1Ah register), except that it does not cancel any ongoing fault cool down time count.
The priority is defined as followings:
OSS code ≤ MBPn_2-0 : when the OSS code is received, the corresponding channel is powered off.
OSS code > MBPn_2-0 : OSS code has no impact on the channel
|MBPn_2-0 0x27/28 Register||Multi Bit Priority||OSS Code for Channel Off|
|0||0||0||Highest||OSS = ‘000’|
|0||0||1||2||OSS = ‘000’ or ‘001’|
|0||1||0||3||OSS ≤ ‘010’|
|0||1||1||4||OSS ≤ ‘011’|
|1||0||0||5||OSS ≤ ‘100’|
|1||0||1||6||OSS = any code except ‘111’|
|1||1||1||Lowest||OSS = any code|
The priority reduces as the 3-bit value increases. Thus, a channel with a "000" setting has the highest priority, while one with a "111" setting has the lowest.
It is permissible to apply the same settings to multiple channels. Doing so will result in all channels with the same setting will be disabled when the appropriate OSS code is presented.
For 4-pair wired Ports, these bits control the individual Channel response. In order for both pair sets of a 4-pair wire Port to be disabled, both channels need to have the same MBP setting otherwise it is possible for only one pair set to be disabled.
In the event a singular channel of a 4-pair dual signature PD is turned off due to OSS or other reason, power may be reapplied to that channel by setting the PWON bit in 0x19h provided the detection and classification are still valid and the Power Allocation settings in 0x29 are sufficient based on the assigned classification of the powered channel.
The turn off procedure due to OSS is similar to a channel reset or change to OFF mode, with the exception that OSS does not cancel any ongoing fault cool down timers. the table below includes the bits that will be cleared when a channel is disabled due to OSS:
|Register||Bits to be Reset|
|0x04||CLSCn and DETCn|
|0x06||DISFn and PCUTn|
|0x08||STRTn and ILIMn|
|0x0C-0F||Requested Class and Detection|
|0x10||PGn and PEn|
|0x14||CLEn and DETEn|
|0x1C||ACn and CCnn|
|0x1E-21||2P Policing set to 0xFFh|
|0x2A-2B||4P Policing set to 0xFFh|
|0x2D||NLMnn, NCTnn, 4PPCTnn, and DCDTnn|
|0x30-3F||Channel Voltage and Current Measurements|
|0x44 - 47||Detection Resistance Measurements|
|0x4C-4F||Assigned Class and Previous Class|
There is no memory of any preceding 3-bit OSS commands. Each 3-bit OSS command is processed immediately (prior to the end of the last OSS MBP pulse) based on the MBPn settings for each Channel. Any attempt to shutdown additional Channels thereafter will require additional 3-bit OSS commands.