Datasheet LTC3884, LTC3884-1 (Analog Devices) - 103

LTC3884/LTC3884-1
PMBus COMMAND DETAILS SMBALERT_MASK
The SMBALERT_MASK command can be used to prevent a particular status bit or bits from asserting ALERT as they are asserted. Figure 45 shows an example of the Write Word format used to set an ALERT mask, in this case without PEC. The bits in the mask byte align with bits in the specified status register. For example, if the STATUS_TEMPERATURE command code is sent in the first data byte, and the mask byte contains 0x40, then a subsequent External Overtemperature Warning would still set bit 6 of STATUS_TEMPERATURE but not assert ALERT. All other supported STATUS_TEMPERATURE bits would continue to assert ALERT if set. Figure 46 shows an example of the Block Write – Block Read Process Call protocol used to read back the present state of any supported status register, again without PEC. SMBALERT_MASK cannot be applied to STATUS_BYTE, STATUS_WORD, MFR_COMMON or MFR_PADS_LTC3884. Factory default masking for applicable status registers is shown below. Providing an unsupported command code to SMBALERT_MASK will generate a CML for Invalid/Unsupported Data.
SMBALERT_MASK Default Setting: (Refer Also to Figure 2) STATUS RESISTER ALERT Mask Value MASKED BITS
STATUS_VOUT 0x00 None STATUS_IOUT 0x00 None 1 7 1 1 8 1 8 1 8 1 1 SLAVE SMBALERT_MASK STATUS_x S W A A A MASK BYTE A P ADDRESS COMMAND CODE COMMAND CODE 3884 F47
Figure 48. Example of Writing SMBALERT_MASK
1 7 1 1 8 1 8 1 8 1 SLAVE SMBALERT_MASK BLOCK COUNT S W A A STATUS_x A A … ADDRESS COMMAND CODE (= 1) COMMAND CODE 1 7 1 1 8 1 8 1 1 Sr SLAVE BLOCK COUNT R A A MASK BYTE NA P ADDRESS (= 1) 3884 F48
Figure 49. Example of Reading SMBALERT_MASK
STATUS_TEMPERATURE 0x00 None STATUS_CML 0x00 None STATUS_INPUT 0x00 None STATUS_MFR_SPECIFIC 0x11 Bit 4 (internal PLL unlocked), bit 0 (FAULT pulled low by external device)
MFR_CLEAR_PEAKS
The MFR_CLEAR_PEAKS command clears the MFR_*_PEAK data values. A MFR_RESET command will also clear the MFR_*_PEAK data values. This write-only command has no data bytes. Rev. F For more information www.analog.com 103 Document Outline Features Applications Typical Application Description Table of Contents Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Overview Main Control Loop EEPROM Power-Up and Initialization Soft-Start Time-Based Sequencing Voltage-Based Sequencing Shutdown Light-Load Current Operation Switching Frequency and Phase PWM Loop Compensation Output Voltage Sensing INTVCC/EXTVCC Power Output Current Sensing and Sub Milliohm DCR Current Sensing Input Current Sensing PolyPhase Load Sharing External/Internal Temperature Sense RCONFIG (Resistor Configuration) Pins Fault Detection and Handling Status Registers and ALERT Masking Mapping Faults to FAULT Pins Power Good Pins CRC Protection and ECC Serial Interface Communication Protection Device Addressing Responses to VOUT, IIN and IOUT Faults Output Overvoltage Fault Response Output Undervoltage Response Peak Output Overcurrent Fault Response Responses to Timing Faults Responses to VIN OV Faults Responses to OT/UT Faults Internal Overtemperature Fault Response External Overtemperature and Undertemperature Fault Response Responses to Input Overcurrent and Output Undercurrent Faults Responses to External Faults Fault Logging Bus Timeout Protection Similarity Between PMBus, SMBus and I2C 2-Wire Interface PMBus Serial Digital Interface PMBus Command Summary PMBus Commands *Data Format Applications Information Current Limit Programming ISENSE0± and ISENSE1± Pins Inductor DCR Sensing Inductor Value Calculation Inductor Core Selection Low Value Resistor Current Sensing Slope Compensation and Inductor Peak Current Power MOSFET and Optional Schottky Diode Selection Variable Delay Time, Soft-Start and Output Voltage Ramping Digital Servo Mode Soft Off (Sequenced Off) INTVCC/EXTVCC Power Topside MOSFET Driver Supply (CB, DB) Undervoltage Lockout CIN and COUT Selection Fault Indication Open-Drain Pins Phase-Locked Loop and Frequency Synchronization Minimum On-Time Considerations External Temperature Sense Input Current Sense Amplifier External Resistor Configuration Pins (RCONFIG) Voltage Selection Frequency Selection Phase Selection Address Selection Using RCONFIG Efficiency Considerations Programmable Loop Compensation Checking Transient Response PolyPhase Configuration Master Slave Operation PC Board Layout Checklist PC Board Layout Debugging Design Example Additional Design Checks Connecting the USB to I2C/SMBus/PMBus Controller to the LTC3884 in System LTpowerPlay: An Interactive GUI for Digital Power PMBus Communication and Command Processing PMBus Command Details Addressing and Write Protect General Configuration Commands On/Off/Margin PWM Configuration Voltage Input Voltage and Limits Output Voltage and Limits Output Current and Limits Input Current and Limits Temperature External Temperature Calibration Timing Timing—On Sequence/Ramp Timing—Off Sequence/Ramp Precondition for Restart Fault Response Fault Responses All Faults Fault Responses Input Voltage Fault Responses Output Voltage Fault Responses Output Current Fault Responses IC Temperature Fault Responses External Temperature Fault Sharing Fault Sharing Propagation Fault Sharing Response Scratchpad Identification Fault Warning and Status Telemetry NVM Memory Commands Store/Restore Fault Log Operation Fault Logging Block Memory Write/Read Typical Applications Package Description Revision History Typical Application Related Parts