Datasheet

RSKRX210 5. User Circuitry
R20UT0302EG0200 Rev. 2.00 Page 14 of 41
Jul 09, 2012
5. User Circuitry
5.1 Reset Circuit
A reset control circuit is not fitted to the RSK, as the MCU is capable of voltage and power-on detection. Resets are
handled internally, and reset switch is connected directly to nRES on the MCU (pin 10).
5.2 Clock Circuit
A clock circuit is fitted to the RSK to generate the required clock signal to drive the MCU, and associated
peripherals. Refer to the RX210 hardware manual for details regarding the clock signal requirements, and the
RSKRX210 board schematics for information regarding the clock circuitry in use on the RSK. Details of the
oscillators fitted to the RSK are listed in Table 5-1 below.
Crystal Function Default Placement Frequency Device Package
X1 Main MCU crystal. Fitted 20MHz Encapsulated, SMT
X2 External clock oscillator Not fitted 20MHz Encapsulated, SMT
X3 Real time Clock Fitted 32.768kHz Encapsulated, SMT
Table 5-1: Oscillators
5.3 Switches
There are four switches located on the RSK board. The function of each switch and its connection is shown in
Table 5-2. For further information regarding switch connectivity, refer to the RSKRX210 board schematics.
Switch Function MCU Connection
RES When pressed, the microcontroller is reset. nRES, Pin 10
SW1 Connects to an IRQ input for user controls. IRQ1, Pin 19
SW2 Connects to an IRQ input for user controls. IRQ3, Pin 17
SW3/ADTRG Connects to an IRQ input for user controls. The switch is also connected
to an ATRG input, and is used to trigger AD conversions.
IRQ4, Pin 16 &
ADTRG0n*, Pin 98
Table 5-2: Switch Connections
* Connected via link resistor R301