nRF24E1 Nordic VLSI, nRF24E1 Datasheet - Page 42

• Manufacturer Part Number: nRF24E1
• Description: 2.4Ghz RF Transceiver With Embedded 8051 Compatible Microcontroller And 9 Input, 10 Bit ADC
• Manufacturer: Nordic VLSI

PRODUCT SPECIFICATION
Figure 5-2 Typical use of A/D with 2 ratiometric inputs
When EXTREF (ADCCON.4) is set to 0 and ADCSEL (ADCCON.3-0) selects an
input AIN
the ratio between the voltage on the selected input, and the internal bandgap reference
(nominally 1.22V).
if single ended input : AINi voltage = 1.22 V * ADCDATA / 2
if differential input : (AINi - AIN
Where N is the number of bits set in ADCRES (ADCSTATIC.1-0) and ADCDATA is
the result bits in ADCDATAH (and ADCDATAL if N > 8).
This mode of operation is normally selected for sources where the voltage is not
depending on the supply voltage.
When ADCSEL (ADCCON.3-0) is set to 8, the ADC will use the internal bandgap
reference (nominally 1.22V), and the input is 1/3 of the voltage on the VDD pins. The
result in ADCDATAx is thus directly proportional to the VDD voltage.
VDD voltage = 3.66 V * ADCDATA / 2**N
Where N is the number of bits set in ADCRES (ADCSTATIC.1-0) and ADCDATA is
the result bits in ADCDATAH (and ADCDATAL if N > 8).
Nordic VLSI ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone [phone] - Fax [phone]
Revision: 1.0
R2
R1
i
(e.g. AIN
R3
0
to AIN
7
), the result in ADCDATAx is directly proportional to
0
) voltage = 1.22 V * (ADCDATA -2
AREF
AIN1
AIN0
SUPPLY
VDD
QhtrÃ#!ÂsÃ(&
**N
**(N-1)
) / 2
**N
July 2003