Schematic

Interface and Logic Conversion
VCC must be 3.7-5.5V
Internal DC-DC will use the
following:
900mA @ 5V
1100mA @ 3.7V
RFID Module
SJ1 and SJ2 select
between PCB antenna
and the u.FL connector.
Note: This device operates in the 860MHz
and 920MHz bands. Other devices operating
near these bands will be affected and
affect the performance of the reader.
See 'Antenna Considerations' of
Design Guide when using an
external antenna.
u.FL
Hardware
Serial
Software
Serial
External Power
Shield and Serial Select
Default is PCB antenna.
Not Populated
Open JP1 if powering from
a source that you do not
want feeding back to USB
These 3 GPIO-LV pins are
3.3V tolerant. Do not expose
them to 5V.
Decreased size of RF pad to avoid GND pad on module
Finalized trace antenna design and matching network
Changes on v10:
Added thermals to user solderable GND connections
Caution: Module gets hot
when reading at full power
Opened up heatsink area on bottom of PCB
This buffer does not operate
when VCCA > VCCB. VCC must
be greater than 3.3V.
1.2-3.6V 1.65-5.5V
VCCA ≤ VCCB
TXB0104
3.3V
3.3V
3.3V
GND
GNDGND
GND
GND GND
GND
VCC
VCC
3.3V
GND
GND
3.3V
GND
VCCVCC
GNDGND
GND
GND
GND
VCC
VCC
GND
GND
3.3V
GND
GND
RED
GND
3.3V
GND
VCC
ESD Diode
3.9nH
Buzzer
GND
U2
VCCA
1
A1
2
A2
3
A3
4
A4
5
GND
7
VCCB
14
B1
13
B2
12
B3
11
B4
10
OE
8 1
2
3
4
5
6
1
2
J4
RX
TX
D2
*D3
D4
*D5
*D6
D7
D8
*D9
*D10
*D11
D12
D13
A0
A1
A2
A3
A4
A5
VIN
RES
5V
AREF
GND
GND
GND
3.3V
IOREF
SDA
SCL
1
2
1
2
3
D1
1
2
3
U3
U4
Nano
GND
1
GND
2
GND
3
GND
4
GND
5
GND
6
GND
7
GND
8
GND
9
VOUT
10
ENABLE
11
GPIO1
12
GPIO2
13
GPIO3
14
GPIO4
15
VIN
16
VIN
17
GND
18
GND
19
UART_TX
20
UART_RX
21
RFU
22
RFU
23
RFU
24
RFU
25
RFU
26
RFU
27
RFU
28
GND
29
GND
30
GND
31
GND
32
GND
33
GND
34
GND
35
GND
36
GND
37
GND
38
RF
39
GND
40
GND
41
GNDP1
GND_PAD1
GNDP2
GND_PAD2
L1
SG1
ENABLE
ENABLE
GPIO1
GPIO1
RXI
RXI
RXI
TXO
TXO
TXO
ENABLE-LV
ENABLE-LV
TXO-LV
TXO-LV
RXI-LV
RXI-LV
GPIO1-LV
GPIO1-LV
GPIO2-LV
GPIO2-LV
GPIO3-LV
GPIO3-LV
GPIO4-LV
GPIO4-LV
v10
N. Seidle
Released under the Creative Commons
Attribution Share-Alike 4.0 License
https://creativecommons.org/licenses/by-sa/4.0/
Design by: