SLOS866F May 2014 – March 2018 DRV2604L
PRODUCTION DATA.
The library data contents can take two forms which are voltage-time pair and linear ramp. The voltage-time pair method implements a set and wait protocol, which is an efficient method of actuator control for most types of waveforms. This method becomes inefficient when ramping waveforms is desired, therefore a linear ramp method is also supported which linearly interpolates a set of voltages between two amplitude values. Both methods require only two bytes of data per set point. The linear ramp method uses a minimum of four bytes so that linear interpolation can be done to the next set point. The most significant bit of the voltage value is reserved to indicate the linear ramping mode.
Data is stored as interleaved voltage-time pairs. Voltage in the voltage-time pair is a 7-bit signed number with range –63 to 63 when in bidirectional mode (BIDIR_INPUT = 1), and a 7-bit unsigned number with a range of 0 to 127 when in unidirectional mode (BIDIR_INPUT = 0). The MSB of the voltage byte is reserved for the linear ramping mode.
The Time value is the number of ticks that the Voltage will last. The size of the tick depends on the PLAYBACK_INTERVAL bit (in register 0x1F). If PLAYBACK_INTERVAL = 0 the absolute time is number of ticks × 5 ms. If PLAYBACK_INTERVAL = 1 the absolute time is number ticks × 1 ms.
When the most significant bit of the Voltage is high, the engine interprets a linear interpolation between that voltage and the following voltage point. The following voltage point can either be a part of a regular voltage-time pair, or a subsequent ramp. The following lists the sequence of bytes:
The engine creates a linear interpolation between Voltage1 and Voltage2 over the time period Time1, where Time1 is a number of 5-ms ticks. The start value for the ramp is the 7-bit value contained in Voltage1. The end amplitude is the 7-bit value contained in Voltage2. The MSB in Voltage2 can indicate a following voltage-time pair or the starting point in a subsequent ramp.