Datasheet
INTB
Channel 0
Conversion N
Channel 1
Conversion N
Channel 0
Conversion N+1
Channel 1
Conversion N+1
Channel 0
Channel 1
x
x
I2C
Case 1: No Data Loss
Case 2: Data Loss
Case 3: Data Loss
I2C Transaction #2 reads:
Channel 0 conversion N
Channel 1 conversion N
I2C Transaction #2 reads:
Channel 0 conversion N+1
Channel 1 conversion N
Channel 0 Conversion N was overwritten
when conversion N+1 for Channel 0
completed
I2C Transaction #2 reads:
Channel 0 conversion N+1
Channel 1 conversion N+1
Channel 0 Conversion N was overwritten when
Conversion N+1 completed
Channel 1 Conversion N is overwritten when
Conversion N+1 completed
Time
Results of Delays in reading after INTB assertion
Chan 0 conversion N
complete and available in
Register 0x00
INTB assert
Chan 1 conversion N
complete and available in
Register 0x02
INTB assert with
completion of Conversion
N-1
I2C transaction #1: read
Data N-1
& INTB deassert
I2C read
#2
INTB
x
x
I2C
I2C read
#2
INTB
x
x
I2C
I2C read
#2
Chan 0 conversion N+1
complete and available in
Register 0x00
x
x
x
x
x
x
I2C transaction #1: read
Data N-1
& INTB deassert
I2C transaction #1: read
Data N-1
& INTB deassert
48
LDC1612
,
LDC1614
SNOSCY9A –DECEMBER 2014–REVISED MARCH 2018
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Product Folder Links: LDC1612 LDC1614
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Figure 58. Data Readback Timing
The STATUS register (Address 0x18) flags UNREADCONVx monitor the accesses to the DATAx registers.
When the DATAx_MSB register is read, the DATAx_LSB register is updated with the corresponding LSB
conversion data, and the UNREADCONVx flag is cleared. If the DATAx_LSB register alone is read, it will not
update and will continuously return data corresponding to the last DATAx_MSB register read.
As shown in Figure 58 , if the I2C data readback is delayed, then it is possible to lose older, unread conversion
results. Monitoring the UNREADCONVx flags are useful to assess whether data loss is occurring.
A delayed read of previous conversion results can produce the condition in which reading the STATUS register
immediately after INTB asserts shows that Channel 0 has no unread data (where the UNREADCONV0 flag is 0),
but other channels do have unread data indicated by the corresponding UNREADCONVx flags.