8

There is no need in normal operation to read the Direct

Comparator output bits, except to directly read the fault state

when CS goes low or to cross-check on the filtered OL and

SG fault data. If the Direct Comparator data is ignored, then

only 16 bits of SPI data is read. In this case the last 3 bits in

the 16 bit sequence is the first 3 bits of Direct Comparator

data which can be ignored.

Data read from a SPI interface starts with the first clock

pulse. The CS and R/W inputs cannot be changed while

reading data from the shift register. And, as noted, an inter-

nal low on the shift register input causes low data bits to fol-

low the 21 bits of diagnostic data.

While the Write/Store operation calls for 6 bits of data, a SPI

write will output 8 bits. The first 2 bits transmitted should be

dummy bits. The 3-bit is the Test bit which should be low for

normal operation. The Test bit is used to facilitate testing in

the manufacturing process and is not recommended for

other use. The 6 programmable bits are described in the

section on Diagnostic Write Operation.

Pin Descriptions

charge pump is used to boost the Power MOSFET gate

drive. This allows a single 5V supply to satisfy all logic and

drive requirements.

OUT1 - OUT4 - Low-side output drivers with 0.62

Ω (OUT1

and OUT2) or 0.57

Ω (OUT3 and OUT4) on resistance. The

outputs are provided with over current shutdown and over

voltage clamping. Additionally, open-load and short-to-

ground detection is carried out when the outputs are ON.

IN1 - IN4 - Active-low CMOS logic inputs which control the

output stages OUT1 - OUT4. These inputs are provided with

pull-up resistors.

RST - Active-low logic-level reset input with internal pull-up

resistor.

CLK - Clock input for synchronous serial interface with inter-

nal pull-up resistor. This input must be high when CS transi-

tions from high to low.

CS - Active-low chip select input for serial interface. This

input has an internal pull-up resistor.

R/W - Read/write control pin for serial interface. This input

controls whether the TXD pin is an input or output. This input

has an internal pull-up resistor.

TXD - Bidirectional data pin for serial interface. When R/Wis

high diagnostic data can be read from HIP0082. When R/W

is low, 6 bits may be written to the internal program register.

FIGURE 2. SERIAL INTERFACE TIMING DIAGRAM

CLK

CS

R/W

TXD

ZZZZZ

ZZ

ZZ = HIGH IMPEDANCE

FIGURE 3. SERIAL INTERFACE WRITE OPERATION

CS

R/W

TXD

ZZZZ

FSB

T

T

T

T

TEST

ISC

ZZZZ

CLK

HIP0082, HIP0084