Datasheet
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
Fault
--
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
Command/response
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.