pca9922 NXP Semiconductors, pca9922 Datasheet - Page 10

• Manufacturer Part Number: pca9922
• Description: 8-channel Constant Current Led Driver With Output Error Detection
• Manufacturer: NXP Semiconductors

NXP Semiconductors
PCA9922_1
Product data sheet
7.2.6 Exit error detect mode
7.2.7 Error detection data
The ‘Exit error detect mode’ sequence is used to exit the error detect mode of operation
and resume normal mode. This is a 5-clock timing sequence using CLK, OE and LE. This
sequence consists of LE being held inactive for all five clocks. OE is active in the second
clock for one and only one clock.
The PCA9922 will return a logical 1 for each output pin that has an error condition
detected as described in
open circuit or short-circuit at the output pin. Once the Capture Fault sequence has
completed, the resultant fault/output error data may be shifted out of the device by issuing
8 clocks and reading the data at the SDO pin. If more than one device is connected in
series, then more than 8 clocks will be needed to shift all of the data from all of the devices
through to the last SDO pin in the chain.
Figure 9
Fig 8.
shows a complete error detection sequence.
Timing for ‘Exit Error Detect Mode’ command
8-channel constant current LED driver with output error detection
Rev. 01 — 15 January 2009
Table 4
CLK
OE
LE
and
Figure 8
Table
shows the timing for this sequence.
5. An error condition may be either an
002aad206
PCA9922
© NXP B.V. 2009. All rights reserved.
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