Evaluation Kit for CMX7x6x
PE0601-xxxx
©
2011 CML Microsystems Plc
24
UM0601/2
The CMX7x6x device audio input amplifiers for IP1 and IP2 are configured as ac coupled, unity
gain, inverting amplifiers. The inputs to these circuits are fed from connectors J1 and J2
respectively.
The CMX7x6x device speaker outputs, SPKR1 and SPKR2, are fed to connectors J3 and J4
respectively. The SPKR1 output can drive an 8ohm speaker and requires that the driver supply,
SPKR_3V3, be connected via jumpers in-circuit between pins 3, 4 and 7, 8 of header J8.
Connector J13 provides access to auxiliary ADCs 1 to 4 and auxiliary DACs 1 to 4 of the
CMX7x6x device.
6.1.6 RF Transceiver Interface
The RF Transceiver interface, J22, is a 60-way right-angled connector with all of the following
signals:
•
Serial interface (from J10 – separate from C-BUS interface)
•
CMX7x6x GPIO
•
5V and -5V Power (direct from PCB input supply - unregulated). May be isolated by removing
R65 and R66 respectively.
•
Clock input (external clock option for CMX7x6x, selected at J6). R67 must be fitted with a
0ohm link to use this option.
•
I and Q differential inputs and outputs
•
Audio inputs 1 and 2 and speaker 2 output (32ohm)
•
All auxiliary ADCs and DACs
•
Digital and analogue grounds
The connector is made by JAE and is part number TX24-60R-LT-H1E. The mating half is part
number TX25-60P-LT-XXX. Both parts are available in the UK from Digi-Key.
6.1.7 Instrumentation Interface
An instrumentation interface has been provided to enable connection of the differential I and Q
signals to laboratory equipment that has only single-ended connections. Use of this section of the
PE0601 requires an additional negative supply rail, nominally –5 volts.
The input path has an effective gain of 6dB.
The input path is configured for, nominally, 0 volts offset in the differential signal input to the
CMX7x6x. This can be made adjustable by removing resistors R1 and R6 and replacing them
with 50kohm potentiometers in positions VR1 and VR2 for the I and Q input paths respectively.
Bourns type 3386P or similar will fit the footprints provided.
There are also two spare op-amps in this section that are configured as unity-gain buffers with the
input tied to analogue ground. Further component footprints are provided so that these can be
reconfigured and test pads are provided for input and output.
6.1.8 Digital Interfacing
Connector J7 provides access to all general purpose I/O lines and to a synchronous serial port.
Use of these signals is Function Image
TM
dependent. In some cases they will have no function.
See relevant CMX7x6x documentation.
Connector J11 is configured as a C-BUS master and compatible with CML evaluation kits with C-
BUS slave connectors. Two more chip selects and other GPIO signals can be routed to this
connector with jumpers at header, J14. Use of this feature is also Function Image
TM
dependent.