projects / sigrok-dumps.git / blame
| Commit | Line | Data |
|---|---|---|
| bde79982 MB |
1 | ------------------------------------------------------------------------------- |
| 2 | NXP PCA9571 | |
| 3 | ------------------------------------------------------------------------------- | |
| 4 | ||
| 5 | The NXP PCA9571 chip is an 8-bits I²C output expander. | |
| 6 | ||
| 7 | Details: | |
| 8 | https://www.nxp.com/products/analog/interfaces/ic-bus/ic-general-purpose-i-o/remote-8-bit-general-purpose-outputs-for-1-mhz-i2c-bus:PCA9571 | |
| 9 | https://www.nxp.com/docs/en/data-sheet/PCA9571.pdf | |
| 10 | ||
| 11 | ||
| 12 | Logic analyzer setup | |
| 13 | -------------------- | |
| 14 | ||
| 15 | The logic analyzer used was a Hobby Components HCTEST0006 (at 2 MHz): | |
| 16 | ||
| 17 | Probe I²C signal | |
| 18 | ---------------------- | |
| 19 | 0 SDA | |
| 20 | 1 SCL | |
| 21 | ||
| 22 | ||
| 23 | Data | |
| 24 | ---- | |
| 25 | ||
| 26 | The sigrok command line used was: | |
| 27 | ||
| 28 | sigrok-cli -d fx2lafw -c samplerate=2mhz --time <time> \ | |
| 29 | --channels 'D0=SDA,D1=SCL' -o <filename.sr> | |
| 30 | ||
| 31 | ||
| 32 | This is a set of example captures of NXP PCA9571 I/O accesses. | |
| 33 | ||
| 34 | Three traces are included: | |
| 35 | ||
| 36 | - pca9571_simple.sr: a simple output write operation. | |
| 37 | ||
| 38 | - pca9571_sequence.sr: 64 consecutive write operations. | |
| 39 | ||
| 40 | - pca9571_warning.sr: this produces a warning because the first read value | |
| 41 | is different from the expected one (the PCA9571 start-up 8-bits port | |
| 42 | status is high logic level 0xFF). This may occur if the first monitored | |
| 43 | operation is a read operation and the PCA9571 is not in its default state | |
| 44 | or if the PCA9571 reboots during the monitoring. |