L9780 datasheet(37/56 Pages) STMICROELECTRONICS

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L9780

Digital interface description

Bit 31: STBHTH

This bit selects the heater short to battery threshold as follows:

STBHTH=’0’ => 250 mV;

STBHTH=’1’ => 425 mV;

The possible ranges of these thresholds are specified in Table 13.

If the device receives an SPI command in order to modify STBHTH bit in the middle of a

measurement cycle, it stores the new information and applies it at the beginning of the new

measurement cycle. STBHTH bit value reported in the output register is the value used in

the last measurement cycle.

Default state for this bit after power on reset: 0.

Bit 30 - 24: ITPT[6..0]

These bits are used to set the RCT1 switch time pulse duration (tR), as specified in section

Table 16.

If the device receives a configuration ITPT[6..0]=’0011000’ or less (except 0000000), the

device considers this configuration as ‘0011001’, and shall provide SO response with the

configuration received from SI, even if is ‘0011000’ or less.

If the device receives an SPI command in order to modify ITPT[6..0] bits in the middle of a

measurement cycle, it stores the new information and applies it at the beginning of the new

measurement cycle. ITPT[6..0] bits reported in the output register are the values used in the

last measurement cycle.

For the description of the timing sequence refer to Section 4.12.

Default state for these bits after power on reset: 0000000 (corresponding to disable state).

Bit 23: SNC

This bit selects the synchronized mode for the device (when SNC=’1’) or the free running

mode (when SNC=’0’).

If the device receives an SPI command in order to set SNC=’1’ bit in the middle of a

measurement cycle, it terminates the measurement cycle and discards all the temporary

conversions; then operates in idle configuration until a rising edge on SY pin is detected;

this is the signal necessary to start a new measurement cycle and to clear the measurement

counter.

Default state for this bit after power on reset: 0.

Bit 22 - 16: CBT[6..0]

These bits are used to set the RCT1 band-gap switch time pulse duration (tB), as specified

in Table 16.

If the device receives an SPI command in order to modify CBT[6..0] bits in the middle of a

measurement cycle, it stores the new information and applies it at the beginning of the new

measurement cycle. CBT[6..0] bits reported in the output register are the values used in the

last measurement cycle.

For the description of the timing sequence refer to Section 4.12.

Default state for these bits after power on reset: 0000000.

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