Telegesis (UK) Limited
TG-ETRXn-UG-01-103
19
User Guide
1.04
ETRX1 and ETRX2
©2008 Telegesis (UK) Ltd
ETRXn User Guide (Rev 1.04)
S0A
This read-
only register contains the revision number of the firmware followed by an „A‟ (for AVR) in
case of the ETRX1 or a „X‟ (for XAP2b) in case of the ETRX2.
5.4 I/O-related registers (S0B-S14)
S0B
This register sets the serial port parameters including command echo and flow control.
S0C
On the ETRX2 this register is the pull-up enable register. By default all pull-ups are disabled. For
current sensitive applications it is recommended not to use the build in pull-ups. On the ETRX1 this
register is reserved for future use.
S0D
The current (volatile) data direction of the I/O port.
S0E
The initial (non-volatile) setting of the data direction (S0D) after reset and power-up
S0F
The current (volatile) output buffer of the I/O port
S10
The initial (non-volatile) setting of the output buffer (S0F) after reset and power-up
S11
The input buffer of the I/O port representing the current logic levels on the m
odule‟s input pins.
S12
Reading of the A/D port 1 in millivolts. On the ETRX1 the allowed input range is 0-2550mV and on
the ETRX2 the allowed input range is 0-1200mV.
S13
Reading of the A/D port 2 in millivolts.
S14
On the ETRX2 this register represents the reading of A/D3 in millivolts, if bit 7 of S2E is set. On the
ETRX1 this register is reserved.
Each module has three volatile registers representing the current state of its I/O, namely:
S0D
Data Direction
S0F
Output Buffer
S11
Input Buffer
S0D defines the data direction of each individual pin, where 1 represents an output and 0
represents an input, e.g. setting bit 7 to 1 will turn I/O7 into an output. By default S0D is defined to
be F8 hexadecimal which suits the devboard having three inputs (Buttons 2-4) and five outputs
(LEDs 1-4 and Beeper). Table 1 shows the mapping of the devboard pins to the I/O of the ETRX1
and ETRX2 module.
