Datasheet

LTC2978A
58
2978afa
For more information www.linear.com/LTC2978A
Table 2. Data Block Contents
DATA BYTE* DESCRIPTION
Mfr_vout_peak7[7:0] 43
Mfr_vout_peak7[15:8] 44
Mfr_vout_min7[7:0] 45
Mfr_vout_min7[15:8] 46
47 bytes for preamble
Fault_log [Position_last] 47
Fault_log 48
.
.
.
Fault_log 237 Last Valid Byte
Reserved 238-254
Number of loops
(238-47)/40 = 4.8
*Note:
PMBus data byte numbers start at 1 rather than 0. Position_last is the
first byte returned after BYTE COUNT = OxFF. See block read protocol.
The data returned between bytes 47 and 237 of the previous
table is interpreted using Position_last and the following
table. The key to identifying byte 47 is to locate the DATA
corresponding to POSITION = Position_last in the next
table. Subsequent bytes are identified by decrementing
the value of POSITION. For example: If Position_last = 9
then the first data returned in byte position 47 of a block
read is Read_vin[15:8] followed by Read_vin[7:0] followed
by Status_mfr of page 1. See Table 3.
Table 3. Interpreting Cyclical Loop
POSITION DATA
0 Read_vout0[7:0]
1 Read_vout0[15:8]
2 Status_vout0
3 Status_mfr0
4 Read_vout1[7:0]
5 Read_vout1[15:8]
6 Status_vout1
7 Status_mfr1
8 Read_vin[7:0]
9 Read_vin[15:8]
10 Status_vin
11 Reserved
12 Read_vout2[7:0]
13 Read_vout2[15:8]
14 Status_vout2
15 Status_mfr2
16 Read_vout3[7:0]
Table 3. Interpreting Cyclical Loop
POSITION DATA
17 Read_vout3[15:8]
18 Status_vout3
19 Status_mfr3
20 Read_temperature_1[7:0]
21 Read_temperature_1[15:8]
22 Status_temp
23 Reserved
24 Read_vout4[7:0]
25 Read_vout4[15:8]
26 Status_vout4
27 Status_mfr4
28 Read_vout5[7:0]
29 Read_vout5[15:8]
30 Status_vout5
31 Status_mfr5
32 Read_vout6[7:0]
33 Read_vout6[15:8]
34 Status_vout6
35 Status_mfr6
36 Read_vout7[7:0]
37 Read_vout7[15:8]
38 Status_vout7
39 Status_mfr7
Total Bytes =40
The following table fully decodes a sample fault log read
to help clarify the cyclical nature of the operation.
MFR_FAULT_LOG DATA BLOCK CONTENTS
PREAMBLE INFORMATION
BYTE
NUMBER
DECIMAL
BYTE
NUMBER
HEX DATA DESCRIPTION
0 00 Position_last
[7:0] = 9 Position of
Fault-Log
Pointer When
Fault Occured.
1 01 SharedTime[7:0] 41-Bit Share-
Clock Counter
Value When
Fault Occurred.
Counter LSB
Is in 200µs
Increments.
2 02 SharedTime[15:8]
3 03 SharedTime[23:16]
4 04 SharedTime[31:24]
PMBus COMMAND DESCRIPTION