ETRX357 Development Kit
©2016 Silicon Labs
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ETRX357DVK Product Manual (Rev 1.12)
I/O breakout:
JP1 and JP2 give access to the I/O on the ETRX357 module. The individual pins are labelled on the
circuit board, and the pin numbering (PA0, PB1 etc) matches that of the EM357 chip inside the
module.
Pin
Devboard functionality
PA0
Button1
PA1
Button2
PA2
Temp sensor supply
PA3
Light sensor supply
PA5
Bootloader button
PB0
Button3
PB1
TXD
PB2
RXD
PB3
CTS
PB4
RTS
PB5
ADC0 (Temp sensor reading)
PB6
Button4
PB6
LED1
PB7
Buzzer
PC0
LED2
PC1
ADC3 (Light sensor reading)
Table 4. I/O Connectivity on development board
Flow Control Selection:
JP5 is used to connect the RTS and CTS lines used for the flow control to
the host. By default flow control is disabled and the corresponding lines of the module are used as
standard I/Os (see the AT command dictionary on how to enable flow control), so the default setting
of JP5 does not connect those lines to the host as shown in Figure 5. When flow control is enabled
JP5 must be set as shown in Figure 6. Please make sure the jumpers are only set to this
configuration when flow control is enabled as otherwise I/Os driving against each other (via a
protective resistor) will increase the current consumption.
Figure 5. No Flow Control (default)
Figure 6. Flow control enabled