SDO

SCK

CSN

CSN

µP

SDO

SDI

SCK

CSN

SCK

CSN

SCK

SDO

SDI

SDO

SDI

no.1

no.2

no.3

D99AT438

Figure 8. Cascading Several Stepper motor drivers.

byte for no. 3

byte for no. 2

byte for no. 1

SCK

EN

CSN

D99AT439

SDO

of

µP

Figure 9. Control sequence for 3 Stepper motor drivers.

Test condition for all propagation times (unless otherwise specified)

HIGH

Symbol

Parameter

Test Conditions

Min.

Typ.

Max.

Unit

SCK-Frequency

DC

2MHz

SCK stable before and after

CSN = 0

100

ns

Width of SCK high pulse

200

ns

Width of SCK low pulse

200

ns

SDI setup time

80

ns

SDI hold time

80

ns

SDO delay time (CL = 50pF)

100

ns

SDO high Z CSN high

100

ns

Setup time ENABLE to SCK

30

µs

Propagation delay SPI to

2 (*)

µs

(*) Measured at a transition from High impedance (Bridge off) to bridge on. (Reversing polarity takes about 1

µs longer because the bridge first

turns off before turning on in reverse direction).

Table of bits

bit5,bit4 : current range of bridge A (Outputs A1 and A2)

bit3

: polarity of bridge A

bit2,bit1 : current range of bridge B (Outputs B1 and B2)

bit0

: polarity of bridge B

bit7,bit6 : Error1 and Error 2

Cascading several Devices

Cascading several devices can be done using the SDO output to pass data to the next device. The

whole frame now consists of n byte. n is the number of devices used.

L9935

13/19