Hardware Description
T8xC5121 Starter Kit User Guide
3-9
4186E–SCR–05/04
3.3
Reset
The on-chip Power-on Reset function generates an internal Reset at power-up.
The external reset push button is provided to easily generate a warm reset during the
ISP process. See Figure 3-1.
3.4
Clock
Crystal can be installed on the Y2 socket.
To use an external Clock, the input must connected to the optional J1 connector and a
jumper must be placed at JP19. See Figure 3-1.
3.5
EA Switch
EA switch inside the SW6 Dip switch is by default connected to Vcc.
Figure 3-2. Default Configuration: switches opened
3.6
INT1 Switch
The INT1 configuration switch (SW6 dip switch) selects whether or not the INT1 push
button is connected to port pin P3.3 on the microcontroller. See Figure 3-1.
3.7
Serial Port
The Board supports a MAX232 at U5 (See Figure 3-1) to convert RS-232 voltage levels.
The serial I/O P3.0/RXD, P3.1/TXD can be disconnected using the JP5, JP6 jumpers.
3.8
LEDs
The JP13 and JP14 jumpers placed in series with the LED0 and LED1 can be used to
monitor the LED current or to disconnect the LEDs.
3.9
Smart Card
Interface
3.9.1
Card Detection
Card detection, by default, uses the on-chip internal pull-up register and the jumper JP9
connected to Vss. This configuration detects the low level input.
Another configuration can be used to detect a high level input when the card is inserted.
This is done using the jumpers JP8 and JP15. In this case, it is necessary to first discon-
nect the internal pull-up resistor, using accompanying software. See Section “Software
Description”.
EA
INT1
SW6
EA=1
INT1 switch opened
1
0
