L9935

Functional description

Doc ID 5198 Rev 10

23/29

5.16

Application information

For driving a stepper motor we suggest to use the following codes. The columned ’SDO

correct’ shows the data returned at SDO in correct function. The columns presented under

’Error cases’ display the diagnosis bits if errors are detected.

Examples of control sequences.

These sequences are intended to give the user a good starting point for his software

development. Besides these two there are further possibilities how to implement control

sequences for this device (other currents, quarters step etc.).

Double errors: Double errors will create composite codes by an AND operation between

columns of the same dominance. Open and short to VS are the least dominant error codes.

(first 6 error code columns). Short to ground is the second dominant error code. detection of

short to gnd will overwrite error codes of the least dominant kind (open, short to VS).

Temperature pre alarm and thermal shut down are the most dominant error codes. Thermal

pre alarm returns error code 00 but the device still is working and returns the appropriate

operation code (bits 0..5).

Thermal shut down returns error code 00 and turns off the device. The opcode returned

corresponds the action eventually performed (bit 0..5 become 1).

For example open bridge A and simultaneously open bridge B will lead to error code 01 by

performing an AND operation between the two corresponding columns.

Table 10.

Full step mode control sequences and diagnosis response

SDI

SDO

correct

Error cases and SDObit7, bit6

--

A

O

P

E

N

B

O

P

E

N

A1

S

H

O

R

T

VS

A2

S

H

O

R

T

VS

B1

S

H

O

R

T

VS

B2

S

H

O

R

T

VS

A1

(1)

S

H

O

R

T

GND

A2

(1)

S

H

O

R

T

GND

B1

(1)

S

H

O

R

T

GND

B2

(1)

S

H

O

R

T

GND

therm.

therm.

alarm

shut down

(reset

operating

codes)

bit

76543210 76543210

76

76

76

76

76

76

76

76

76

76

76

76543210

XX111111

SDO present last data or 11111111 in case prev. state was standby

XX011011

XX010011

XX010010

XX011010

XX011011

XX010011

XX010010

XX011010

11111111

11011011

11010011

11010010

11011010

11011011

11010011

11010010

11

11

01

11

01

11

01

11

11

11

11

01

11

01

11

01

11

11

01

01

01

11

01

01

11

01

01

11

01

01

01

11

11

11

11

01

01

01

11

01

11

01

01

01

11

01

01

01

11

10

01

11

10

10

01

11

11

11

10

10

01

11

10

10

11

10

10

01

11

10

10

01

11

11

11

10

10

01

11

10

00

00

00

00

00

00

00

00

00111111

00111111

00111111

00111111

00111111

00111111

00111111

00111111

1.

Motor resistance approximately 10

 and V

S = 12V. So a short to ground only is detected on one branch of the bridge.

Lower resistivity of the motor may lead to detection of short to ground on both branches of the bridge leading to code 10 on

all steps.