SCA3000 DEMO KIT
User Manual
9.1 Known
Issues
9.1.1 Floating SCA3000 CLK-pin
With MCU software version 0.9.95 the CLK-pin of SCA3000 (pin #4) is configured to floating
instead of GND. SCA3000 will operate normally, but floating the CLK-pin may cause bigger current
consumption values for SCA3000 than normally. If such thing is noticed, the CLK line (marked also
on the silkscreen of the USB interface card) can be grounded.
This feature is fixed with MCU software version 0.9.95-r1.
9.1.2 Changing the serial bus type
The MCU needs to be reset (by pressing the reset button, see Figure 1) when changing between
the two available serial bus types (SPI & I2C). This thing can happen when user changes the used
SCA3000 component type.
9.1.3 Interference from USB communication
Capacitor C22 (Figure 16) connects the USB cable connector body to the GND net of the USB
interface board. The capacitor value is updated from 470 pF to 100 nF in order to decrease the
interferences in USB supply voltage (USB_VCC net in Figure 16). USB serial communication
causes the interference in to the supply voltage provided by USB port.
The value of the capacitor C22 is 100 nF in the SCA3000 DEMO KITs that have been assembled
since end of June 2006.
VTI Technologies Oy
20/21
www.vti.fi Doc.Nr.
8259300.11
Rev.0.11
