Datasheet

Table Of Contents
Programming manual L6470
60/73 DocID16737 Rev 7
Any attempt to read an inexistent register (wrong address value) causes the command to be
ignored and the WRONG_CMD flag to rise at the end of the command byte as if an
unknown command code were sent.
9.2.5 Run (DIR, SPD)
The Run command produces a motion at SPD speed; the direction is selected by the DIR
bit: '1' forward or '0' reverse. The SPD value is expressed in step/tick (format unsigned fixed
point 0.28) that is the same format as the SPEED register (see Section 9.1.4 on page 42).
Note: The SPD value should be lower than MAX_SPEED and greater than MIN_SPEED
otherwise the Run command is executed at MAX_SPEED or MIN_SPEED respectively.
This command keeps the BUSY flag low until the target speed is reached.
This command can be given anytime and is immediately executed.
9.2.6 StepClock (DIR)
The StepClock command switches the device in Step-clock mode (see Section 6.7.5 on
page 26) and imposes the forward (DIR = '1') or reverse (DIR = '0') direction.
When the device is in Step-clock mode, the SCK_MOD flag in the STATUS register is raised
and the motor is always considered stopped (see Section 6.7.5 and Section 9.1.22 on page
55).
The device exits from Step-clock mode when a constant speed, absolute positioning or
motion command is sent through SPI. Motion direction is imposed by the respective
StepClock command argument and can by changed by a new StepClock command without
exiting Step-clock mode.
Events that cause bridges to be forced into high impedance state (overtemperature,
overcurrent, etc.) do not cause the device to leave Step-clock mode.
The StepClock command does not force the BUSY flag low. This command can only be
given when the motor is stopped. If a motion is in progress, the motor should be stopped
and it is then possible to send a StepClock command.
Any attempt to perform a StepClock command when the motor is running causes the
command to be ignored and the NOTPERF_CMD flag to rise (see Section 9.1.22).
Table 41. Run command structure
Bit 7Bit 6Bit 5Bit 4Bit 3Bit 2Bit 1Bit 0
0101000DIR From host
XXXX SPD (Byte 2) From host
SPD (Byte 1) From host
SPD (Byte 0) From host
Table 42. Stepclock command structure
Bit 7Bit 6Bit 5Bit 4Bit 3Bit 2Bit 1Bit 0
0101100DIRFrom host