C 8 0 5 1 F 8 0 0 - D K
10
Rev. 0.2
7.4. Switches and LEDs (J3)
Two push-button switches are provided on the target board. The switch labeled ‘RESET’ (SW1 in schematic) is
connected to the reset pin (RST) of the C8051F800. Pressing this switch puts the device into its hardware-reset
state. The switch labeled “P1.4” (SW2 in schematic) is connected to the C8051F800’s general purpose I/O (GPIO)
pin through headers. Pressing this switch generates a logic low signal on the port pin. Remove the shorting block
from the header to disconnect this switch from the port pin. The port pin signal is also routed to a pin on the J1 I/O
connector. See Table 1 for the port pins and headers corresponding to each switch.
Two capacitive sense switches are also provided on the target board. The operation of these switches needs
appropriate code running on the C8051F800 MCU that can sense the state of the switch. Note that no shorting
blocks should be present on J3[15-16] and J3[17-18] for proper operation of these switches. See Section 6.3.
"Capacitive Sense Switch Example‚" on page 6 for details about example source code.
Six LEDs are provided on the target board to serve as indicators. The red LED labeled “PWR” is used to indicate
the presence of power to the target board. Another red LED labeled “USB” is used to indicate a valid USB
connection via the USB connector labeled “COMM.” Note that this LED will light up only after CP210x device
drivers are loaded successfully on the PC. The four green LEDs labeled with port pin names P1.0_LED through
P1.3_LED are connected to the C8051F800’s GPIO pins P1.0 through P1.3, respectively, via the header J3.
Remove the shorting block from the header to disconnect the LED from the port pin. The port pin signal is also
routed to a pin on the J1 I/O connector. See Table 1 for the port pins and headers corresponding to each LED.
Table 1. Target Board I/O Descriptions
Description
I/O
Header(s)
RESET (SW1)
Reset
none
P1.4 (SW2)
P1.4
J3[9-10]
P1.5 (Capacitive Sense)
P1.5
J3[15-16]
*
P1.6 (Capacitive Sense)
P1.6
J3[17-18]
*
P1.0_LED (Green LED)
P1.0
J3[1-2]
P1.1_LED (Green LED)
P1.1
J3[3-4]
P1.2_LED (Green LED)
P1.2
J3[5-6]
P1.3_LED (Green LED)
P1.3
J3[7-8]
PWR (Red LED)
Power
none
USB (Red LED)
USB Active
none
*Note
: Shorting blocks should NOT be present at these headers for
the proper operation of the capacitive sense switches.
