PIN DESCRIPTION [Pin Types: I = Input, O = Output, P = Power, A = Analog (passive)]

Power

Pin Number

Pin Name

Pin Type

Description

12, 17

24,

3

VPOWER

VDIG

P

Positive supply, nominally 5V.

7, 42, 64

GND

P

Ground.

10

I

All analog signals are referenced to this voltage, nominally 2V.

59

POR

0

POWER ON RESET - Goes low when the supply voltage is below the

VOLTAGE GOOD threshold. POR is an open collector output with an

internal 20k

Ω pull-up.

61

POR_DLY

A

POR DELAY. An external parallel RC network from this pin to ground

sets the time the POR signal stays active after voltage good.

62

POR_FILT

A

An external capacitor from this pin to ground provides filtering for the

5

CPC

A

Charge pump capacitor

6

CPL

A

Charge pump inductor

Microprocessor Interface

Pin Number

Pin Name

Pin Type

Description

25

26

27

28

29

30

31

32

D7

D6

D5

D4

D3

D2

D1

D0

I/O

I/O

I/O

I/O

I/O

I/O

I/O

I/O

An 8-bit bidirectional data bus which is connected to the internal

registers.

38

RD

I

READ A low level on this pin allows the bus to be driven by the IC.

39

WR

I

A low level on WRITE allows the IC to read data from the system bus.

35

MC_CS

I

CHIP SELECT A low level on this pin selects the IC for bus

transactions.

41

SYSCLK

I

Microprocessor clock used for internal timing.

33

34

35

A0

A1

A2

I

I

I

The lowest three bits of the system address bus; used to address

internal registers

37

AS

I

ADDRESS STROBE The address appearing on A [0:2] is latched on

the falling edge of the AS pulse.

43

MC_ERR

O

A maskable interrupt signal which is asserted low when an error flag in

the Status Register is set. The output is open-drain with an internal

20K

Ω pull-up.

40

DTACK

O

An open drain, active low signal used for asynchronous bus

transactions.

Brushless, Sensorless Motor Driver and 8 bit D/A

Pin Number

Pin Name

Pin Type

Description

47

SPIN_DAC

O

The output of an 8 bit D/A used for the command to the spindle driver.

48

SPIN_CMD

I

The input to the spindle driver transconductance amplifier.

45

COIL_CT

I

The center tap of the motor is connected to this pin.

53

57

60

COIL_U

COIL_V

COIL_W

O

The motor coils are driven by these outputs. Back EMF is also sensed

at these pins.

L6245

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