Get error flags halting – Pololu Jrk USB User Manual
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input value. The jrk can recover from the error by receiving four good pulses in a row. This error does not occur
in Analog Input Mode or Serial Input Mode.
• Bit 4: Input disconnect
This error occurs when the input is above the Absolute maximum or below the Absolute minimum (these
parameters can be set in the configuration utility). Additionally, when using the Detect disconnect with AUX
option in Analog Input Mode, the jrk periodically tests to see whether the input potentiometer is disconnected
and generates this error if it finds that it is (
• Bit 5: Feedback disconnect
This error occurs when the feedback is above the Absolute maximum or below the Absolute minimum (these
parameters can be set in the configuration utility). The absolute maximum and absolute minimum can be set
using the configuration utility. Additionally, when using the Detect disconnect with AUX option in Analog
Feedback Mode, the jrk periodically tests to see whether the feedback potentiometer is disconnected and
generates this error if it finds that it is (
• Bit 6: Maximum current exceeded
This error occurs when the motor current limit is exceeded. The limit can be set using the configuration utility
(
).
• Bit 7: Serial signal error
A hardware-level error that occurs when a byte’s stop bit is not detected at the expected place. This can occur if
you are communicating at a baud rate that differs from the jrk’s baud rate.
• Bit 8: Serial overrun
A hardware-level error that occurs when the UART receive buffer is full. This error should not occur during
normal operation.
• Bit 9: Serial RX buffer full
A firmware-level error that occurs when the firmware’s buffer for bytes received on the RX line is full and a byte
from RX has been lost as a result. This error should not occur during normal operation.
• Bit 10: Serial CRC error
This error occurs when the jrk is running in CRC-enabled mode and the cyclic redundancy check (CRC) byte at
the end of the command packet does not match what the jrk has computed as that packet’s CRC (
).
In such a case, the jrk ignores the command packet and generates a CRC error.
• Bit 11: Serial protocol error
This error occurs when the jrk receives an incorrectly formatted or nonsensical command packet. For example,
if the command byte does not match a known command or an unfinished command packet is interrupted by
another command packet, this error occurs.
• Bit 12: Serial timeout error
When the serial timeout is enabled (
), this error occurs whenever the timeout period has elapsed
without the jrk receiving any valid serial commands. This timeout error can be used to shut down the motors in
the event that serial communication between the jrk and its controller is disrupted.
• Bits 13-15: Reserved
These bits do not represent any errors; they will always read as zeroes.
Get Error Flags Halting
Compact protocol: 0xB3
Pololu protocol: 0xAA, device number, 0x33
This command generates a two-byte serial response reporting which errors are currently stopping the motor, and
it clears the corresponding error bits (except for the Awaiting Command error bit). This command is useful for
determining why your motor is not turning, and for clearing any latched errors that are enabled. This command will
not report any errors that have been disabled in the configuration utility, because those errors do not stop the motor.
Pololu Jrk USB Motor Controller User's Guide
© 2001–2014 Pololu Corporation
4. Using the Serial Interface
Page 34 of 45