Toradex Colibri - Analog Inputs; Parallel Memory Bus (External Memory Bus); Analog Input Signals; Memory Bus Signals

Colibri Carrier Board Design Guide
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2.16 Analog Inputs
The Colibri modules feature up to four analog input channels. The supported sampling rates and
resolution are dependent on the modules. The input voltage range for most modules is from 0V to
3.3V. Please check the related datasheet for the input voltage range. The ADC reference is the
analog input voltage rail. The analog input channels are not designed to be used for high precision
measurement tasks. The interface can be used for battery voltage monitoring (additional circuit
required), ambient light sensors, or simple analog joystick input devices.
2.16.1 Analog Input Signals
Colibri
Pin
Colibri
Signal Name
I/O
Type
Power
Rail
Description
8
Analog Input <0>
I
Analog
3.3V
ADC input (3.3V max)
6
Analog Input <1>
I
Analog
3.3V
ADC input (3.3V max)
4
Analog Input <2>
I
Analog
3.3V
ADC input (3.3V max)
2
Analog Input <3>
I
Analog
3.3V
ADC input (3.3V max), some modules might use this input for
the five-wire resistive touch interface.
Table 22: Analog Input Signals
2.16.2 Unused Analog Inputs Signal Termination
The unused analog input signals can be left unconnected or tied to the ground. It is recommended
to disable the corresponding inputs in the driver or disable the whole ADC block if not used.
2.17 Parallel Memory Bus (External Memory Bus)
The Colibri form factor reserves several module edge pins as a parallel memory bus. This bus can
be used for interfacing high-speed peripherals like FPGAs, DSPs, Ethernet controllers, CAN, and
controllers. The supported data and address width, as well as some control signals, are dependent
on the module. Some modules do not even provide a compatible parallel bus on the dedicated
signal pins. Carefully check the datasheets of the modules for more information about the
supported modes.
Additionally, the Pinout Designer tool can be a valuable source of information. This tool allows
comparing the different bus modes and data/address widths. Special care has to be taken if a
carrier board is designed for PXA270: Since the Colibri PXA270 uses the parallel memory bus also
internally, it is not allowed to use the pins for anything else than for this dedicated function. Proper
glue logic is needed or the pins need to be left unconnected.
2.17.1 Memory Bus Signals
Colibri
Pin
Colibri
Signal Name
I/O
Type
Power
Rail
Description
111
BUS_A00
O
CMOS
3.3V
Address signals. The actual available number of address signals
varies by the modules.
113
BUS_A01
O
CMOS
3.3V
115
BUS_A02
O
CMOS
3.3V
117
BUS_A03
O
CMOS
3.3V
119
BUS_A04
O
CMOS
3.3V
121
BUS_A05
O
CMOS
3.3V
123
BUS_A06
O
CMOS
3.3V
125
BUS_A07
O
CMOS
3.3V
110
BUS_A08
O
CMOS
3.3V
112
BUS_A09
O
CMOS
3.3V
114
BUS_A10
O
CMOS
3.3V