Analog Integrated Circuit Device Data



Freescale Semiconductor

29

33813

The Retry Enable bit, bit 7, when set will allow the output to turn on for a short period and off for a long period when an over-

current condition is present. The open load (OL) current sink disable allow the current sink to be turned off when using the driver

as an LED driver to prevent ghosting, where the LEDs appears to be partially on due to the OL current sink. It can also be turned

off to measure the output device leakage. The Inrush delay bit, when set (by default for the Lamp driver) waits an additional time

before annunciating an over-current condition. This is done to allow for the inrush current of an incandescent lamp. The internal

PWM duty cycles (D/C) are controlled by the lower 7 bits in the corresponding SPI control register. The external duty cycles are

provided by the MCU on the input pin of the corresponding output driver.

5.1.22 VRSP, VRSN Inputs, VRSOUT Output

The 33813 contains a VRS input conditioning circuit that employs a differential input. VRSP and VRSN are the positive and

to within the safe operating range of the circuit. It is important to provide external 15 k current limiting resistors to prevent damage

mounted toothed wheel to provide an angle clock and RPM data to the MCU. This circuit provides a comparator with multiple

thresholds, which are programmed via the SPI to allow the VRS circuit to handle different sensors and the wide dynamic range

of the VRS output at engine speeds from crank to running. The output of this circuit is provided on the VRSOUT pin, which is a

5.0 Volt logic level signal to the MCU. The comparator threshold values can also be controlled automatically based on the input

signal amplitude. The output of the comparator contains a programmable one shot, noise blanking circuit. The time value of this

blanking pulse can be selected via the SPI as a percentage of the last input high (or low) pulse. The VRSOUT output can also

be divided and sent to the TACHOUT pin to drive a tachometer.

Table 9. LAMPOUT SPI Configuration Register

7

6

5

4

3

2

1

0

Retry

Enable

(0)

x

(0)

x

(0)

OL

Current

Sink

Enable

(1)

In- Rush

Delay

(1)

x

(0)

PWM

Freq.

1

(0)

PWM

Freq.

0

(0)

Table 10. PWM Duty Cycles

Bits 1, 0

PWM Frequency

PWM D/C

00

None or on ext. pin

None or on ext. pin

01

100 Hz

Internal

10

1.0 KHz

Internal

11

On ext pin

Internal

Table 11. SPI VRS Manual Configuration Register

SPI VRS Manual Parameters Configuration Register

Bits 7, 6, 5, 4

Threshold Values (nominal)

0000

0.01 - 28 mV

(Tolerance not specified below 110 mV threshold. Only specified for monotonicity.)

0001

0.01 - 36 mV

(Tolerance not specified below 110 mV threshold. Only specified for monotonicity.)

0010

3.0 - 36 mV

(Tolerance not specified below 110 mV threshold. Only specified for monotonicity.)

0011

8.0 - 48 mV

(Tolerance not specified below 110 mV threshold. Only specified for monotonicity.)