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KXICS Theory of Operation
the rest of the board until the signal DTR is active high on pin 4 of the serial
connector, J6.
Test points are provided for common (TP1), power input VDD (TP3), switched
main power VDD_SW (TP5), power to the MCU VDD_MCU (TP4), and VTST
(TP2).
3.4.1.1 Main Switched Power
Power to the MCU sockets and circuitry is switched on and off using the DTR
signal into the serial interface (J6). When DTR is low, the power to the MCU
socket is off, and the amber LED is off. When DTR is asserted high, transistor
Q3 will turn on FET Q2 which provides power to the MCU circuitry. if W2 is
selected positions 1 and 2. VTST voltage is sent to the MCU along with the reset
signal being held low briefly following power-up. The MCU is forced to
power-up in the Monitor Mode.
NOTE:
The source of power for the MCU is selected by jumper2. Refer to Section 2,
Table 2-1.
The amber LED, DS2, lights when there is power to the MCU socket.
CAUTION:
There is no over-current protection on the board protecting against
catastrophic failures if the MCU is powered from the target. Equipment damage
can result.
The power to the MCU is selected by jumper W2. With the jumper in the 5V
position, the MCU will be powered by the 5V circuitry, i.e., from the plug in the
power supply). With W2 in the LO V position, the MCU will be powered by the
on-board low voltage regulator (U6). The low voltage is selected by jumper W1
which has preset voltages of 3.3V, 3.0V, 2.7V, 2.2V, 2.0V, and a poteniometer
for adjusting the voltage.
CAUTION:
The MCU may be set to operate at a variety of voltages. Ensure the selected
voltage matches the voltage of the target. Failure to do so can result in
equipment damage.
M68ICS08KX In-Circuit Simulator
MOTOROLA
User’s Manual
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