24
USB interface
The current standard in connecting with a PC, the USB interface, permits quick transfers and taking the power
supply from the computer. Thanks to the existence of circuits converting the USB interface to RS-232, its
implementation in own equipment is very simple and cheap. The drawing below presents a way of equipping
the MMnet102 module with an USB interface, using the MMusb232 module. After installing VCP drivers, such
an interface is seen in the system as a virtual COM port, thus its software on the PC should surely provide no
problems.
TXLED
1
PWRCTL
2
PWREN
3
TxDEN
4
RI
5
DCD
6
DSR
7
DTR
8
CTS
9
RTS
10
RxD
11
TxD
12
NC
13
GND
14
RESET
15
RESETO
16
GND
17
3V3OUT
18
GND
19
SLEEP
20
RXLED
21
IOVCC
22
EXTVCC
23
PORTVCC
24
MMusb232
GND
GND
GND
RX
TX
1k5
1k5
+5V
+5V_USB
PE1(TxD0) lub PD3(TxD1)
PE0(RxD0) lub PD2(RxD1)
USB Connector
Figure 17
Connection of the USB port to the MMnet102.
Additional information on the MMusb232 module can be found on the web page:
http://www.propox.com/products/t_93.html?lang=en
Radio link
Fitting the system with the possibility of communicating via a wireless path provides a possibility of easy
control and collection of measurement data from system elements dispersed in the object, without the need to
install any cabling. Thanks to the existence of integrated transceivers the construction of such links is
relatively simple. The figure presents a way of connecting an MMnet102 module with a radio minimodule
MMcc1000. To execute such a connection, five I/O microcontroller lines are needed, including one breakpoint
input. An optional connection of the RSSI output with the input of the A/D converter permits the measurement
of the strength of the received signal.
GND
GND
GND
Antenna
+3.3V (from MMnet102)
ADCx
INTx
Pxx
Pxx
Pxx
Pxx
CHP
J1_6
DIO
J1_5
DCLK
J1_4
PCLK
J1_3
PDATA
J1_2
PALE
J1_1
GND
J2_6
RSSI
J2_5
VCC
J2_4
GND
J2_3
ANT
J2_2
GND
J2_1
MMcc1000
J1
J2