RFM22
Register 0Fh. ADC Configuration
Bit
D7
D6
D5
adcsel[2:0]
R/w
D4
D3
D2
adcref[1:0]
D1
adcgain[1:0]
R/w
D0
adcstart/
adcdone
R/w
Name
Type
R/w
Reset value = 00000000
Bit
Name
adcstart/adcdone ADC Measurement Start Bit.
Function
7
Reading this bit gives 1 if the ADC measurement cycle has been finished.
ADC Input Source Selection.
The internal 8-bit ADC input source can be selected as follows:
000:
001:
010:
011:
100:
101:
110:
111:
Internal Temperature Sensor
GPIO0, single-ended
GPIO1, single-ended
6:4
adcsel[2:0]
GPIO2, single-ended
GPIO0(+) – GPIO1(–), differential
GPIO1(+) – GPIO2(–), differential
GPIO0(+) – GPIO2(–), differential
GND
ADC Reference Voltage Selection.
The reference voltage of the internal 8-bit ADC can be selected as follows:
3:2
1:0
adcref[1:0]
0X:
10:
11:
bandgap voltage (1.2 V)
VDD / 3
VDD / 2
ADC Sensor Amplifier Gain Selection.
The full scale range of the internal 8-bit ADC in differential mode (see adcsel)
can be set as follows:
adcgain[1:0]
adcref[0] = 0:
adcref[0] = 1:
FS = 0.014 x (adcgain[1:0] + 1) x VDD FS = 0.021 x (adcgain[1:0] + 1) x VDD
89
Tel: +86-755-82973805
Fax: +86-755-82973550
E-mail: sales@hoperf.com
http://www.hoperf.com
HOPERF [ HOPERF ]
