Atmel XMEGA-A1 Xplained Evaluation Board ATAVRXPLAIN ATAVRXPLAIN Scheda Tecnica
Codici prodotto
ATAVRXPLAIN
10
Atmel AVR1924
8370C-AVR-12/11
9 Known issues
9.1 Light sensor
The output range of the light sensor is 0V – 3.3V. The ADC reference must therefore
be high enough to match the output range of the light sensor when performing
measurements.
be high enough to match the output range of the light sensor when performing
measurements.
9.2 USB test points
Touching the test points of the USB data lines on the reverse side of the board while
there is an ongoing communication, might interrupt the device and cause the device
to stop responding. The kit must be reconnected to start working properly again.
there is an ongoing communication, might interrupt the device and cause the device
to stop responding. The kit must be reconnected to start working properly again.
9.3 PDI initialization
Because JTAG_TDO and PDI_DATA are connected on the PCB for this kit, JTAG
must be disabled on the device in order to use PDI. The reason for this is that when
JTAG is enabled it will enable a pull-up internally on TDO which interferes with the
PDI initialization sequence.
must be disabled on the device in order to use PDI. The reason for this is that when
JTAG is enabled it will enable a pull-up internally on TDO which interferes with the
PDI initialization sequence.
The connection of JTAG_TDO with PDI_DATA is also an issue when the application
on the device uses the JTAG_TDO pin e.g. by driving this pin actively or by using a
pull-up. This will interfere with ongoing PDI communication. Additionally, when JTAG
is disabled and the application is driving the JTAG_TDO pin it might even not be
possible to establish a PDI connection. A workaround for this is to add a ~1k resistor
from PDI_CLK/RESET to GND. This will keep the device in reset while PDI is
enabled. When a PDI connection is established the flash can be erased or JTAG can
be enabled in order to "unlock" the kit.
on the device uses the JTAG_TDO pin e.g. by driving this pin actively or by using a
pull-up. This will interfere with ongoing PDI communication. Additionally, when JTAG
is disabled and the application is driving the JTAG_TDO pin it might even not be
possible to establish a PDI connection. A workaround for this is to add a ~1k resistor
from PDI_CLK/RESET to GND. This will keep the device in reset while PDI is
enabled. When a PDI connection is established the flash can be erased or JTAG can
be enabled in order to "unlock" the kit.