SIM5218E Hardware Design
Table 21
：
meanings of status LED
Status
Data
Voice
Always On
Searching Network
Searching Network/Call Connect
200ms ON, 200ms OFF Data Transmit
800ms ON, 800ms OFF Registered network
Registered Network
Off
Power Off
GPIO4 can be used to control RF close or on, the Flight Mode Switch logic table is shown
below. User can
use AT Command to read or to write GPIO2, GPIO3, GPIO5 status (High or
Low level).
Table 22
：
logic of GPIO4
SIM5218E_ Hardware Design_V1.06
2012.09.21
42
Use AT
Command to read or write GPIO2, GPIO3, GPIO5 status (High or Low level).
NOTE
：
For SIM5218E, GPIO0, GPIO2, GPIO3 and GPIO5 can be multiplex function, user
can use them as PCM interface to connect extend codec. Please refer section 3.18 and
document [1] for detail information.
3.14 ADC interface
SIM5218E has an analog-to-digital converter (ADC) that is available for
digitizing analog signals
such as battery voltage, temperature and so on, it’s on PIN 30, namely HKADC0, This HKADC0
is 8 bit successive-approximation circuit, and performance specification is shown in the following
table:
Table 23
：
ADC Characteristics
Specification
Min
Typ
Max
Unit
Comments/Conditions
Resolution
8
Bits
differential
nonlinearity
-0.75
+0.75
LSB
Integral nonlinearity -1.5
+1.5
LSB
Gain Error
-2.5
+2.5
%
Offset Error
-3
+3
LSB
.
Analog Vdd = ADC reference
300 kHz - 1.2 MHz sample rate
Input Range
GND
2.6
V
3dB input
bandwidth
2500
Source resistance = 50
Ω
Input serial
resistance
1
k
Ω
Sample and hold switch resistance
Input capacitance
12
pF
Power-down to
5
μ
s
GPIO4 Status
Module Action
L
Flight Mode: RF is closed.
H
Normal Mode: RF is working.
