32
CY3280-MBR2 CapSense Express with SmartSense Auto-Tuning Kit Guide, Doc. # 001-71857 Rev. *C
Hardware
shows the block diagram of the CY3280-MBR kit. The block diagram can be classified
into four sections: Power, CY8CMBR2110 functional blocks, I2C to USB, and Connectors (USB-IIC
and 44-pin expansion connector). Each section is explained in detail here.
Figure 4-2. Block Diagram
4.1
Power Block
This block consists of the power source, series pass switch, power LED, and the CY8CMBR2044
CapSense controller. The kit supports three power sources.
Table 4-1. Power Source
The series pass switch, which is controlled by the CY8CMBR2044 CapSense controller is responsi-
ble for the power supplied to the CY8CMBR2110 functional block. To power the kit, at least one of
the above sources should be active. Touch the CapSense-based
Power
button to see the LED glow-
ing and ensure that the kit is powered.
The kit has various protection circuits driven by the CY8CMBR2044 chip:
■
A fuse is present in the power block to limit the external consumption to 200 mA.
■
A diode is present at VDD-Ext to limit the input voltage to 6 V.
■
ESD protection is enabled for USB lines.
No.
Power Source
Voltage Levels
(Volts)
Power Select Switch
Position
1
AAA batteries provided with the kit
a
a. An estimated battery life of ~40hrs can be achieved on an AAA pack when all blocks are turned on. An estimated battery life of one year
can be achieved on an AAA pack when the unit is in standby/sleep.
3.0
BAT
2
GUI when connected to PC via USB-IIC connector
b
b. GUI has four power options - 1.8 V, 2.5 V, 3.3 V, and 5 V; however, it only supports 3.3 V for this kit. The USB status LED glows when the
kit is connected to PC. USB power LED indicates that the kit is powered through USB.
3.3
GUI
3
External source
c
c. To power the kit in this mode change the switch position to EXT and connect the external voltage source and ground to the VDD_EXT (pin
43) and GND (pin 40) pins respectively of the 44-pin connector.
3.0
EXT
CY8CMBR2110
CapSense
Controller
Ten
CapSense
Buttons
Ten
Output
LEDs
Buzzer
Output
Two
Host
Controlled
LEDs
Expansion
Connector
Flex
‐
PCB/BSM
Board
CY8C24894
CapSense
Controller
USB
‐
I2C/J3
Connector
GUI
Series
pass
Controlled
Switch
CY8CMBR2044
CapSense
Controller
Power/Wake
LEDs
Power
Select
switch
AAA
Batteries
External
Source
GUI
I2C
Vdd
Power
and
Status
LEDs
