C8051T63x-DK
Rev. 0.1
11
7.1. System Clock Sources
The C8051T63x devices feature a calibrated internal oscillator that is enabled as the system clock source on reset.
After reset, the internal oscillator operates at a frequency of 24.5 MHz (±2%) by default, but may be configured by
software to operate at other frequencies. Therefore, in many applications, an external oscillator is not required.
However, if you wish to operate the C8051T63x device at a frequency not available with the internal oscillator, an
external oscillator source may be used. Refer to the C8051T63x data sheet for more information on configuring the
system clock source.
7.2. Switches, LEDs, Potentiometer, and IDAC Resistor
Two switches are provided on the motherboard. The RESET switch is connected to the RST pin of the C8051T63x.
Pressing RESET puts the device into its hardware-reset state. The switch labeled “SW” can be connected to the
C8051T63x's general purpose I/O (GPIO) pin P0.7 through header J9. Pressing this switch generates a logic low
signal on the port pin. Remove the shorting block from the J9 header to disconnect the switch from the port pin.
Six LEDs are also provided on the motherboard. The red LED labeled “PWR” (D4), is used to indicate a power
connection to the motherboard. The green LED labeled “RUN” (D10) turns on when the debug circuitry is in a
running state; the red LED labeled “STOP” (D11) turns on when the debug circuitry is in a halted state, and the
orange LED labeled “DEBUG PWR” (D12) indicates whether the debug adapter circuit is being powered through
P5's USB connector. The red LED labeled “VPP” (D7) indicates when the VPP programming voltage is being
applied to the device. The green LED, labeled "LED" (D1), can be connected to the C8051T63x's GPIO pin through
header J9. Remove the shorting block from the header to disconnect the LED from the port pin. The red LED
labeled "USB ACTIVE" (D2) will turn on whenever the CP2103 USB-to-UART bridge is connected to a PC and has
successfully completed enumeration.
Also included on the C8051T63x motherboard is a 10 k
thumbwheel rotary potentiometer, reference number R8.
The potentiometer can be connected to the C8051T63x's P1.6 pin through the J12 header. Remove the shorting
block from the header to disconnect the potentiometer from the port pin.
A 1 k
resistor, reference number R20, is included on the C8051T63x Motherboard to provide a current path to
ground for the IDAC. The resistor can be connected to the IDAC output pin (P0.1) through the J5 header.
Table 1 lists the port pins and headers corresponding to the switches, LEDs, potentiometer, and IDAC resistor.
Table 1. Motherboard I/O Descriptions
Description
Component Name
I/O
Header
SW
SW1
Daughter Card's P0.7
J9 [3-4]
RESET
SW2
Daughter Card's RST/C2CK
None
Green LED labeled "LED"
D1
Daughter Card's P1.3
J9 [1-2]
Green LED labeled "USB ACTIVE"
D2
U2 CP2103's SUSPEND
None
Red LED labeled "PWR"
D4
Daughter Card's VDD
J6, J7
Red LED labeled “VPP”
D7
Daughter Card's P0.2
J11
Green LED labeled "RUN"
D10
Debug Adapter Signal
None
Red LED labeled "STOP"
D11
Debug Adapter Signal
None
Orange LED labeled "DEBUG PWR"
D12
Debug Adapter Signal
None
Potentiometer
R8
Daughter Card's P1.6
J12
IDAC Resistor
R20
Daughter Card's P0.1
J5
Summary of Contents for C8051T630
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Page 15: ...C8051T63x DK Rev 0 1 15 Figure 10 C8051T630 Motherboard Schematic 2 of 2 ...
Page 16: ...C8051T63x DK 16 Rev 0 1 Figure 11 C8051T630 Emulation Daughter Board Schematic ...
Page 17: ...C8051T63x DK Rev 0 1 17 Figure 12 C8051T630 QFN 20 Daughter Board Schematic ...
