L6474PD View Datasheet(PDF) - STMicroelectronics

Part Name

Description

MFG CO.

L6474PD

Fully integrated microstepping motor driver

STMicroelectronics 

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Programming manual

L6474

Address

[Hex]

Register

name

Table 9. Register map (continued)

Register function

Len.

[bit]

Reset

Hex

Reset value

h19

STATUS

Status

16

XXXX

(2)

High impedance state, UVLO/reset

flag set.

h1A RESERVED Reserved address

h1B RESERVED Reserved address

1. R: Readable, WH: writable only when outputs are in high impedance, WR: always writable.

2. According to startup conditions.

Remarks(1)

R

9.1.1

9.1.2

ABS_POS

The ABS_POS register contains the current motor absolute position in agreement to the

selected step mode; the stored value unit is equal to the selected step mode (full, half,

quarter, etc.). The value is in 2's complement format and it ranges from -221 to +221-1.

At power-on the register is initialized to “0” (HOME position).

EL_POS

The EL_POS register contains the current electrical position of the motor. The two MSbits

indicate the current step and the other bits indicate the current microstep (expressed in

step/128) within the step.

Bit 8 Bit 7

STEP

Bit 6

Table 10. EL_POS register

Bit 5

Bit 4

Bit 3

MICROSTEP

Bit 2

Bit 1 Bit 0

9.1.3

9.1.4

When the EL_POS register is written by the user the new electrical position is instantly

imposed. When the EL_POS register is written its value must be masked in order to match

with the step mode selected in the STEP_MODE register in order to avoid a wrong

microstep value generation (see Section 9.1.10 on page 38); otherwise the resulting

microstep sequence is incorrect.

Any attempt to write the register when the outputs are enabled causes the command to be

ignored and the NOTPERF_CMD flag to rise (see Section 9.1.13 on page 41).

MARK

The MARK register contains an absolute position called MARK, according to the selected

step mode; the stored value unit is equal to the selected step mode (full, half, quarter, etc.).

It is in 2's complement format and it ranges from -221 to +221-1.

TVAL

The TVAL register contains the current value that is assigned to the torque regulation DAC.

The available range is from 31.25 mA to 4 A with a resolution of 31.25 mA, as shown in

Table 2 on page 8.

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