Silicon Laboratories Si446 Series, Manual

Page: 26 / 112

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26 Rev. 0.1
3.2.7. GET_ADC_READING
 Summary: Retrieve the results of possible ADC conversions.
 Purpose:

Retrieve the result of the last ADC conversion.
 Command Stream
 Reply Stream
 Parameters:

TEMPERATURE_EN
0 = Don't do ADC conversion of temperature, will read 0 value in reply TEMPERATURE
1 = Do ADC conversion of temperature, result in TEMP_ADC.
Temp in Celsius = ((512 + TEMP_SLOPE) / 4096) x TEMP_ADC – (INTERCEPT / 2 + 256)

BATTERY_VOLTAGE_EN
0 = Don't do ADC conversion of battery voltage, will read 0 value in reply BATTERY_VOLTAGE
1 = Do ADC conversion of battery voltage, results in BATTERY_VOLTAGE. Vbatt = 3*Batt_ADC/1280

ADC_GPIO_EN
0 = Don't do ADC conversion on GPIO, will read 0 value in reply
1 = Do ADC conversion of GPIO, results in ADC_GPIO. Vgpio = 3*GPIO_ADC/1280

ADC_GPIO_PIN[1:0] - Select GPIOx pin. The pin must be set as input
0 = Measure votage of GPIO0
1 = Measure votage of GPIO1
2 = Measure votage of GPIO2
3 = Measure votage of GPIO3

Response:

GPIO_ADC[15:0] - ADC value of voltage on GPIO

BATTERY_ADC[15:0] - ADC value of battery voltage

TEMP_ADC[15:0] - ADC value of temperature sensor voltage of the chip in degrees kelvin

TEMP_SLOPE[7:0] - Slope in the formula of Vtempadc -- Temperature

TEMP_INTERCEPT[7:0] - Intercept in the fromula of Vtempadc -- Temperature
GET_ADC_READING
Command
7 6 5 4 3 2 1 0
CMD 0x14
ADC_EN 000 TEMPERATURE_EN BATTERY_VOLTAGE_
EN
ADC_GPIO_
EN
ADC_GPIO_PIN[1:0]
GET_ADC_READING Reply 7 6 5 4 3 2 1 0
CMD_COMPLETE CTS[7:0]
GPIO_ADC GPIO_ADC[15:8]
GPIO_ADC GPIO_ADC[7:0]
BATTERY_ADC BATTERY_ADC[15:8]
BATTERY_ADC BATTERY_ADC[7:0]
TEMP_ADC TEMP_ADC[15:8]
TEMP_ADC TEMP_ADC[7:0]
TEMP_SLOPE TEMP_SLOPE[7:0]
TEMP_INTERCEPT TEMP_INTERCEPT[7:0]