Mesa HostMot2 Driver

has_bit - (bit i/o) True if the watchdog has bit, False if the watchdog has not bit. If the watchdog has bit and the has_bit bit is True, the user can reset it to False to resume operation.

timeout_ns - (u32 read/write) Watchdog timeout, in nanoseconds. This is initialized to 1,000,000,000 (1 second) at module load time. If more than this amount of time passes between calls to the pet_watchdog() function, the watchdog will bite.

pet_watchdog() - Calling this function resets the watchdog timer and postpones the watchdog biting until timeout_ns nanoseconds later. This function should be added to the servo thread.

in - (Bit, Out) Normal state of the hardware input pin. Both full GPIO pins and I/O pins used as inputs by active module instances have this pin.

in_not - (Bit, Out) Inverted state of the hardware input pin. Both full GPIO pins and I/O pins used as inputs by active module instances have this pin.

out - (Bit, In) Value to be written (possibly inverted) to the hardware output pin. Only full GPIO pins have this pin.

invert_output - (Bit, RW) This parameter only has an effect if the is_output parameter is true. If this parameter is true, the output value of the GPIO will be the inverse of the value on the out HAL pin. Only full GPIO pins and I/O pins used as outputs by active module instances have this parameter. To invert an active module pin you have to invert the GPIO pin not the module pin.

is_opendrain - (Bit, RW) This parameter only has an effect if the is_output parameter is true. If this parameter is false, the GPIO behaves as a normal output pin: the I/O pin on the connector is driven to the value specified by the out HAL pin (possibly inverted), and the value of the in and in_not HAL pins is undefined. If this parameter is true, the GPIO behaves as an open-drain pin. Writing 0 to the out HAL pin drives the I/O pin low, writing 1 to the out HAL pin puts the I/O pin in a high-impedance state. In this high-impedance state the I/O pin floats (weakly pulled high), and other devices can drive the value; the resulting value on the I/O pin is available on the in and in_not pins. Only full GPIO pins and I/O pins used as outputs by active module instances have this parameter.

is_output - (Bit, RW) If set to 0, the GPIO is an input. The I/O pin is put in a high-impedance state (weakly pulled high), to be driven by other devices. The logic value on the I/O pin is available in the in and in_not HAL pins. Writes to the out HAL pin have no effect. If this parameter is set to 1, the GPIO is an output; its behavior then depends on the is_opendrain parameter. Only full GPIO pins have this parameter.

control-type - (Bit, In) Switches between position control mode (0) and velocity control mode (1). Defaults to position control (0).

counts - (s32, Out) Feedback position in counts (number of steps).

enable - (Bit, In) Enables output steps. When false, no steps are generated.

position-cmd - (Float, In) Target position of stepper motion, in user-defined position units.

position-fb - (Float, Out) Feedback position in user-defined position units (counts / position_scale).

velocity-cmd - (Float, In) Target velocity of stepper motion, in user-defined position units per second. This pin is only used when the stepgen is in velocity control mode (control-type=1).

velocity-fb - (Float, Out) Feedback velocity in user-defined position units per second.

dirhold - (u32, RW) Minimum duration of stable Direction signal after a step ends, in nanoseconds.

dirsetup - (u32, RW) Minimum duration of stable Direction signal before a step begins, in nanoseconds.

maxaccel - (Float, RW) Maximum acceleration, in position units per second per second. If set to 0, the driver will not limit its acceleration.

maxvel - (Float, RW) Maximum speed, in position units per second. If set to 0, the driver will choose the maximum velocity based on the values of steplen and stepspace (at the time that maxvel was set to 0).

position-scale - (Float, RW) Converts from counts to position units. position = counts / position_scale

step_type - (u32, RW) Output format, like the step_type modparam to the software stegen(9) component. 0 = Step/Dir, 1 = Up/Down, 2 = Quadrature. In Quadrature mode (step_type=2), the stepgen outputs one complete Gray cycle (00 -> 01 -> 11 -> 10 -> 00) for each step it takes.

steplen - (u32, RW) Duration of the step signal, in nanoseconds.

stepspace - (u32, RW) Minimum interval between step signals, in nanoseconds.

invert_output - (Bit, RW) This parameter only has an effect if the is_output parameter is true. If this parameter is true, the output value of the GPIO will be the inverse of the value on the out HAL pin.

is_opendrain - (Bit, RW) If this parameter is false, the GPIO behaves as a normal output pin: the I/O pin on the connector is driven to the value specified by the out HAL pin (possibly inverted). If this parameter is true, the GPIO behaves as an open-drain pin. Writing 0 to the out HAL pin drives the I/O pin low, writing 1 to the out HAL pin puts the I/O pin in a high-impedance state. In this high-impedance state the I/O pin floats (weakly pulled high), and other devices can drive the value; the resulting value on the I/O pin is available on the in and in_not pins. Only full GPIO pins and I/O pins used as outputs by active module instances have this parameter.

enable - (Bit, In) If true, the pwmgen will set its Not-Enable pin false and output its pulses. If enable is false, pwmgen will set its Not-Enable pin true and not output any signals.

value - (Float, In) The current pwmgen command value, in arbitrary units.

output-type - (s32, RW) This emulates the output_type load-time argument to the software pwmgen component. This parameter may be changed at runtime, but most of the time you probably want to set it at startup and then leave it alone. Accepted values are 1 (PWM on Out0 and Direction on Out1), 2 (Up on Out0 and Down on Out1), 3 (PDM mode, PDM on Out0 and Dir on Out1), and 4 (Direction on Out0 and PWM on Out1, for locked antiphase).

scale - (Float, RW) Scaling factor to convert value from arbitrary units to duty cycle: dc = value / scale. Duty cycle has an effective range of -1.0 to +1.0 inclusive, anything outside that range gets clipped.

pdm_frequency - (u32, RW) This specifies the PDM frequency, in Hz, of all the pwmgen instances running in PDM mode (mode 3). This is the pulse slot frequency; the frequency at which the pdm generator in the Anything I/O board chooses whether to emit a pulse or a space. Each pulse (and space) in the PDM pulse train has a duration of 1/pdm_frequency seconds. For example, setting the pdm_frequency to 2e6 (2 MHz) and the duty cycle to 50% results in a 1 MHz square wave, identical to a 1 MHz PWM signal with 50% duty cycle. The effective range of this parameter is from about 1525 Hz up to just under 100 MHz. Note that the max frequency is determined by the ClockHigh frequency of the Anything I/O board; the 5i20 and 7i43 both have a 100 MHz clock, resulting in a 100 Mhz max PDM frequency. Other boards may have different clocks, resulting in different max PDM frequencies. If the user attempts to set the frequency too high, it will be clipped to the max supported frequency of the board.

pwm_frequency - (u32, RW) This specifies the PWM frequency, in Hz, of all the pwmgen instances running in the PWM modes (modes 1 and 2). This is the frequency of the variable-duty-cycle wave. Its effective range is from 1 Hz up to 193 KHz. Note that the max frequency is determined by the ClockHigh frequency of the Anything I/O board; the 5i20 and 7i43 both have a 100 MHz clock, resulting in a 193 KHz max PWM frequency. Other boards may have different clocks, resulting in different max PWM frequencies. If the user attempts to set the frequency too high, it will be clipped to the max supported frequency of the board. Frequencies below about 5 Hz are not terribly accurate, but above 5 Hz they’re pretty close.

invert_output - (Bit, RW) This parameter only has an effect if the is_output parameter is true. If this parameter is true, the output value of the GPIO will be the inverse of the value on the out HAL pin.

is_opendrain - (Bit, RW) If this parameter is false, the GPIO behaves as a normal output pin: the I/O pin on the connector is driven to the value specified by the out HAL pin (possibly inverted). If this parameter is true, the GPIO behaves as an open-drain pin. Writing 0 to the out HAL pin drives the I/O pin low, writing 1 to the out HAL pin puts the I/O pin in a high-impedance state. In this high-impedance state the I/O pin floats (weakly pulled high), and other devices can drive the value; the resulting value on the I/O pin is available on the in and in_not pins. Only full GPIO pins and I/O pins used as outputs by active module instances have this parameter.

count - (s32, Out) Number of encoder counts since the previous reset.

index-enable - (Bit, I/O) When this pin is set to True, the count (and therefore also position) are reset to zero on the next Index (Phase-Z) pulse. At the same time, index-enable is reset to zero to indicate that the pulse has occurred.

position - (Float, Out) Encoder position in position units (count / scale).

rawcounts - (s32, Out) Total number of encoder counts since the start, not adjusted for index or reset.

reset - (Bit, In) When this pin is TRUE, the count and position pins are set to 0. (The value of the velocity pin is not affected by this.) The driver does not reset this pin to FALSE after resetting the count to 0, that is the user’s job.

velocity - (Float, Out) Estimated encoder velocity in position units per second.

counter-mode - (Bit, RW) Set to False (the default) for Quadrature. Set to True for Up/Down or for single input on Phase A. Can be used for a frequency to velocity converter with a single input on Phase A when set to true.

filter - (Bit, RW) If set to True (the default), the quadrature counter needs 15 clocks to register a change on any of the three input lines (any pulse shorter than this is rejected as noise). If set to False, the quadrature counter needs only 3 clocks to register a change. The encoder sample clock runs at 33 MHz on the PCI Anything I/O cards and 50 MHz on the 7i43.

index-invert - (Bit, RW) If set to True, the rising edge of the Index input pin triggers the Index event (if index-enable is True). If set to False, the falling edge triggers.

index-mask - (Bit, RW) If set to True, the Index input pin only has an effect if the Index-Mask input pin is True (or False, depending on the index-mask-invert pin below).

index-mask-invert - (Bit, RW) If set to True, Index-Mask must be False for Index to have an effect. If set to False, the Index-Mask pin must be True.

scale - (Float, RW) Converts from count units to position units. A quadrature encoder will normally have 4 counts per pulse so a 100 PPR encoder would be 400 counts per revolution. In .counter-mode a 100 PPR encoder would have 100 counts per revelution as it only uses the rising edge of A and direction is B.

vel-timeout - (Float, RW) When the encoder is moving slower than one pulse for each time that the driver reads the count from the FPGA (in the hm2_read() function), the velocity is harder to estimate. The driver can wait several iterations for the next pulse to arrive, all the while reporting the upper bound of the encoder velocity, which can be accurately guessed. This parameter specifies how long to wait for the next pulse, before reporting the encoder stopped. This parameter is in seconds.