2 Errata
Errata and issue description for all board revisions.
Legend
- -
- Erratum is not applicable
- X
- Erratum is applicable
| Category | Short Description | Valid for PCBA Revision | |
|---|---|---|---|
| Rev. 2 | Rev. 3 | ||
| Silkscreen | D0 and CMD Swapped in Silkscreen Next to the SDCARD Socket | X | X |
| Silkscreen | PAC1944 Power Monitor CH3 Silkscreen Arrows Point in the Wrong Direction | X | X |
| Power supply | Inserting USB Cables in a Certain Order may Lead to a Voltage Drop | X | X |
| Power supply | Bridge Reset (MCP2221A/MIC2008) Powers Microcontroller Through I/O Pins | X | X |
| I/O section | LED I/O Expander Cannot Read Low Pin Status | X | X |
| I/O section | Capacitive Touch Buttons and Mechanical Switch SW1 are Unusable | X | - |
| I2C bus | I2C Bus Signal Rise Time not Compliant with 400 kHz Operation | X | - |
2.1 Silkscreen
2.1.1 D0 and CMD Swapped in Silkscreen Next to the SDCARD Socket
Marking of D0 and CMD in the silkscreen is swapped compared to the electrical connection in the PCB. The connections to the microcontroller are correct to communicate with an SDCARD.
- X
- The D0 and CMD silkscreen location is swapped compared to the electrical connection
- ✔
- The D0 and CMD silkscreen location matches the electrical connection
Work Around
None.
Affected PCBA Revisions
| Rev. 2 | Rev. 3 |
| X | X |
2.1.2 PAC1944 Power Monitor CH3 Silkscreen Arrows Point in the Wrong Direction
Arrows are drawn in the silkscreen to indicate the current flow in the PAC1944 power monitor section of the board. The arrows indicating the current flow through channel 3 point in the wrong direction.
- X
- Silkscreen arrows point in the opposite direction of the current flow through channel 3
- ✔
- Silkscreen arrows point in the same direction as the current flow through channel 3
Work Around
None
Affected PCBA Revisions
| Rev. 2 | Rev. 3 |
| X | X |
2.2 Power Supply
2.2.1 Inserting USB Cables in a Certain Order may Lead to a Voltage Drop
Unplugging the USB-C® cable from the Curiosity Nano Explorer while a USB cable is connected to an attached Curiosity Nano microcontroller board causes the input power multiplexer on the Curiosity Nano Explorer to enter a faulty state. Current flows through the body diode of MOSFET Q502, and the output voltage will be about a diode drop lower than the expected 5.0V in this failure state. Currents above 1A may destroy the MOSFET.
The voltage multiplexer can enter the same failure state if a USB-A to USB-C cable is disconnected from the source while a USB cable is connected to an attached Curiosity Nano evaluation kit.
Work Around
Always unplug the USB cable from an attached Curiosity Nano board before unplugging the USB-C cable from the Curiosity Nano Explorer. Do not unplug a USB-C cable connected to the Curiosity Nano Explorer from the source first.
Affected PCBA Revisions
| Rev. 2 | Rev. 3 |
| X | X |
2.2.2 Bridge Reset (MCP2221A/MIC2008) Powers Microcontroller Through I/O Pins
Microcontrollers on Curiosity Nano development boards attached to the socket on the Curiosity Nano Explorer are powered through I/O when the MCP2221A is disabled through the BRIDGE_RESET signal. In some scenarios VCC_VBUS (5V) may oscillate on/off with a ~5 Hz frequency.
Work Around
Do not use the software controlled power off (BRIDGE_RESET) implemented through the MCP2221A/MIC2008
or
disconnect the CNANO I/O from the affected I/O pins:
- Remove jumper JP136 to disconnect PAC-INT2
- Remove jumper JP139 to disconnect BRIDGE_RESET
- Set switch S501 to the mikroBUS™ setting to disconnect the UART TX line from the MCP2221A
- Set switch S500 to "NC" to disconnect the board I2C bus from the PAC1944 and MCP2221A
Affected PCBA Revisions
| Rev. 2 | Rev. 3 |
| X | X |
2.3 I/O Section
2.3.1 LED I/O Expander Cannot Read Low Pin Status
The microcontrollers' I/O pins on Curiosity Nano boards, the pin-header row (J301) next to the LEDs, and I/O expander 1 (MCP23008/U300) are all connected to the LEDs through a resistor network. The voltage on the I/O expander pin is 1.8V when an LED is activated by pulling the CNANO pin low. 1.8V is in the undefined range for the I/O expander pin, and results from read operations cannot be used.
Work Around
None
Affected PCBA Revisions
| Rev. 2 | Rev. 3 |
| X | X |
2.3.2 Capacitive Touch Buttons and Mechanical Switch SW1 are Unusable
The MTCH1030 enters "Touch Tune Data" mode on power-up, disabling the capacitive touch status outputs, and transmits detailed touch data as UART through the OUT2 pin. The touch buttons do not change the output signals, and the mechanical switch SW1 is not usable as a button.
Work Around
Prevent the MTCH1030 from entering "tune data mode" by pulling the TUNE_EN pin high during power-up by replacing C405 with a 10 kΩ resistor.
Affected PCBA Revisions
| Rev. 2 | Rev. 3 |
| X | - |
2.4 I2C Bus
2.4.1 I2C Bus Signal Rise Time not Compliant with 400 kHz Operation
The SDA and SCL rise time is measured to ~440 ns, way above the maximum rise time of 300 ns from the I2C specification for 400 kHz operation. The rise time will increase further if extensions are connected to the Grove, QWIIC, and/or mikroBUS connectors due to the increased I2C bus capacitance.
Work Around
Use 100 kHz communication on the I2C bus
or
replace the I2C pull-up resistors to be compatible with 100 kHz and 400 kHz operation.
I2C PULL-UP A: 2.7 kΩ (R101 and R102)
I2C PULL-UP B: 5.1 kΩ (R505 and R506)
Affected PCBA Revisions
| Rev. 2 | Rev. 3 |
| X | - |