L9654 datasheet(36/59 Pages) STMICROELECTRONICS

36 / 59 page

Functional description

L9654

36/59

DocID14218 Rev 3

Odd parity check includes all 16 bits. “Don’t care” bit is included in the parity check as well.

When bit D12 is set to ‘1’, device executes bit D12 through bit D0. Otherwise, bit D12

through bit D0 is ignored. Diagnostic Mode Response is sent in the subsequent SPI

transmission regardless of bit D12.

The diagnostic currents comprise of diagnostic bias current (IBIAS) and resistance

measurement current (ISRC). Diagnostic bias current is used to run continuity tests, e.g.

short to battery, short to ground, and open circuit tests. During a resistance measurement,

ISRC and ISINK is turned on.

ISRC and ISINK are turned on when bit D8 is ‘1’, bit D9 is ‘1’, bit D11 is ‘0’, and bit D12 is ‘1.’

Otherwise, ISRC and ISINK are off. When bit D11 is set to ‘1’, MOS diagnostic is enabled.

Depending upon the state of bit D10, either a low-side MOS or a high-side MOS is switched

on. When bit D 11 is set to ‘0’, MOS diagnostic is disabled and bit D10 ignored. When bit D9

is set to ‘1’, a diagnostic current source is enabled. Bit D8 determines if IBIAS or ISRC is

switched on. When bit D9 is set to ‘0’, the diagnostic current sources is disabled and bit D8

ignored. Bit D2 through bit D0 selects a specific channel, which is connected.

The decoding scheme of this channel selection is shown ahead.

It is possible to select current source and AOUT independently. Only one channel can

source a diagnostic current at a given time. AOUT is connected to one channel at one time

as well. The diagnostic current and AOUT can be connected to the same channel as well as

to different channels. In this configuration, a short between loop diagnostic can run.

Diagnostic of multiple devices requires the ability to turn on a current source in one device,

while reading AOUT voltage of another device. The differential amplifier reflects the scaled

voltage across SQH and SQL pins. AOUT is connected to the differential amplifier.

Externally, AOUT pin is connected to an ADC input of a processor. When bit D7 is set to ‘1’,

AOUT output is enabled. Otherwise, AOUT is in a high impedance state. Multiple devices

Diagnostic Current Disable (default)

Diagnostic Current Enable

Diagnostic Bias Current, IBIAS, Enable

Resistance Measurement Current, ISRC, Enable

AOUT Disable (default)

AOUT Enable

AOUT/Comparator Channel Select

AOUT: Resistance Measurement (default)

AOUT: Calibration

Diagnostic Current: Channel Select

Table 19. MOSI diagnostic mode message definition (continued)

Bit

State

Description

L9654 датащи(PDF) 36 Page - STMicroelectronics

L9654 датащи(HTML) 36 Page - STMicroelectronics

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59

датащи скачать

ссылки URL