Analog Integrated Circuit Device Data

22

Freescale Semiconductor

33899

FUNCTIONAL DEVICE OPERATION

LOGIC COMMANDS AND REGISTERS

LOGIC COMMANDS AND REGISTERS

SPI INTERFACE AND REGISTER DESCRIPTION

SPI Control Register Definition

An 8-bit SPI allows the system microprocessor to clear the

Fault register, select a programmable current limit, and select

a 1X, 2X, or 4X slew rate. The SPI Control Register bit

definitions are shown in Table 8.

Note At POR, all bits in the register are cleared to 0s.

SPI Fault Register Definition

The fault diagnostic capability consists of one internal 8-bit

Fault register. Table 9 shows the content of the Fault register.

The output load status of the H-Bridge circuit is reported via

the output DO SPI bits. In addition to output fault information,

die temperature warnings and over-temperature conditions

are reported.

transition, followed by 8 SCLK cycles to shift the fault register

impedance mode and clears the fault latches if the FLTCLR

bit is set. The thermal fault is immediately set again if the fault

condition is still present. Accurate fault reporting can only be

obtained by reading the DO line at intervals greater than the

fault timer. A thermal fault will be latched as soon as it occurs.

Note: At POR, all bits in the register are cleared to 0s.

Table 8. SPI Control Register Bit Definitions

8 (MSB)

7

6

5

4

3

2

1 (LSB)

FLTCLR

Not Used

Not Used

Not Used

Current Limit

Current Limit

Slew Time

Slew Time

Bit 8: FLTCLR: 0 = Retain faults; 1 = Clear faults

Bit 7: Not used

Bit 6: Not used

Bit 5: Not used

Bits 4–3: Set Low Side Current Comparator Limits

00 = 4.0A

01 = 5.0A

10 = 6.0A

11 = 8.5A

Bits 2–1: Slew Time

00 = 1X

01 = 2X

10 = 4X

11 = 4X

Table 9. SPI Fault Register Bit Definitions

8 (MSB)

765

43

2

1 (LSB)

ShVIGNP

ShGnd

Open Fault

Over-voltage or

Under-voltage

LS Comparator

EN1, EN2

Status

Die Temp

Die Temp

Bit 7: Short to Ground: 0 = No fault; 1 = S1 or S0 shorted to GND (High Side Linear Current Limit has tripped)

Bit 6: Open Fault: 0 = No fault; 1 = S1 or S0 is Open Circuited

Bit 5: Over-voltage or Under-voltage: 0 = No fault; 1 = Over-voltage/under-voltage fault

Bit 4: Low Side Comparator: 0 = No trip; 1 = Tripped

Bit 3: XOR function of EN1, EN2 inputs. 0 = (EN1 same logic level as EN2). 1 = (EN1 not same logic level as EN2).

Bits 2–1: Die Temperature

00 = T < 140

°C

01 = 140

°C < T < Over-temperature Shutdown

10 = Not Defined

11 = Over-temperature Shutdown (Latched Off)