L9803 datasheet(72/126 Pages) STMICROELECTRONICS

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On-Chip Peripherals

L9803

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T0 = 0143h = 323K (50 Celsius)

VTo = 015Ch = 348 LSB (conversion of 1.7V, sensor output)

and the sensor output is 2V, converted by the ADC in code 0110011001 = 019Ah = 410LSB,

the temperature of the chip is

TEMP = 019Ah * 0143h / 015Ch = 017Ch

equivalent to:

TEMP = 410 * 323 / 348 = 380 K = 107

°C

Note:

The sensor circuit may have two kind of error: one translating its output characteristic up

and down and the other changing its slope. The described trimming recovers only the

translation errors but can not recover slope error. After trimming, being TTRIM the trimming

temperature, the specified precision can be achieved in the range TTRIM-80, max[TTRIM+80,

150

°C]. Precision is related to the read temperature in Kelvin.

5.5.7

CONTROL/STATUS REGISTER (ADCCSR)

Address: 0072h

—

Read/Write

Reset Value: 0010 0000 (20h)

Bit 7,6 = Reserved

Bit 5 =COCO (Read Only) Conversion Complete

COCO is set (by the ADC) as soon as a conversion is completed (results can be read).

COCO is cleared by setting ADST=1 (start of new conversion). If COCO=0 a conversion is

running, if COCO=1 no conversion is running.

Bit 4 = ADIE A/D Interrupt Enable

This bit is used to enable / disable the interrupt function:

0: interrupt disabled

1: interrupt enabled

Bit 3= Reserved

Bit 2= ADST Start Conversion

When this bit is set a new conversion starts. ADST is automatically reset when the

conversion is completed (COCO=1).

Bits 1-0 = CH1-CH0 Channel Selection

These bits select the analog input to convert. See Table 12 for reference.

COCO

ADIE

ADST

CH1

CH0

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