LTC4449 datasheet(101/108 Pages) LINER

101 / 108 page

LTC3882-1

101

Rev A

For more information www.analog.com

PMBus COMMAND DETAILS (Fault Response and Communication)

MFR_FAULT_LOG

The MFR_FAULT_LOG command allows the contents of the fault log to be read. This log is created with a

MFR_FAULT_LOG_STORE command or at the first fault occurrence after a CLEAR_FAULTS or MFR_FAULT_LOG_CLEAR

command. If a fault occurs within the first second after applying power, some earlier pages in the log may not contain

valid data.

This read-only command uses block protocol with 147 bytes of data requiring an estimated data transfer time of 3.4ms

at 400kHz. The tTIMEOUT parameter is extended when this command is executed and a fault log is present.

Fault Log Operation

A conceptual diagram of the fault log is shown in Figure 53. The fault log provides telemetry recording capability to

the LTC3882-1. During normal operation the contents of the status registers, the output voltage readings, temperature

readings as well as peak values of these quantities are stored in a continuously updated buffer in RAM. The operation

is similar to a strip chart recorder. When a fault occurs, the contents are written into EEPROM for nonvolatile storage.

The EEPROM fault log is then locked. The part can be powered down with the fault log available for reading at a later

time. As a consequence of adding ECC, the area in the EEPROM available for fault log is reduced. When reading the

fault log from RAM all 6 events of cyclical data remain. However, when the fault log is read from EEPROM (after a

reset), the last 2 events are lost. The read length of 147 bytes remains the same, but the fifth and sixth events are a

repeat of the fourth event.

38821 F53

TIME OF FAULT

TRANSFER TO

EEPROM AND

LOCK

AFTER FAULT

READ FROM

EEPROM AND

LOCK BUFFER

ADC READINGS

CONTINUOUSLY

FILL BUFFER

RAM BYTES

EEPROM BYTES

•

Figure 53. Fault Log Conceptual Diagram

MFR_FAULT_LOG_CLEAR

The MFR_FAULT_LOG_CLEAR command erases all stored fault log values. After a clear is issued, up to 8ms may be

required to clear related bit 3 in STATUS_MFR_SPECIFIC.

This write-only command has no data bytes.

LTC4449 Datasheet(PDF) 101 Page - Linear Technology

LTC4449 Datasheet(HTML) 101 Page - Linear Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL