User manual

6.8.Oscillator Sources
Crystal oscillators are fitted on the board and used to supply the main/sub clock input to the Renesas microcontroller.
Table 6-12 details the oscillators that are fitted and alternative footprints provided on this board:
Component
Main clock (X1) Fitted 20 MHz (HC/49U package)
Sub clock (X2) Fitted 32.768 kHz (90SMX package)
Table 6-12: Oscillator
6.9.Reset Circuit
The CPU Board includes a simple latch circuit that links the mode selection and reset circuit. This provides an easy method for swapping
the device between Boot mode and Single chip mode. This circuit is not required on customers’ boards as it is intended for providing
easy evaluation of the operating modes of the device on the Renesas Starter Kit. Please refer to the hardware manual for more
information on the requirements of the reset circuit.
The Reset circuit operates by latching the state of the boot switch on pressing the reset button. This control is subsequently used to
modify the MODE pin states as required.
The MODE pin should change state only while the reset signal is active to avoid possible device damage.
The reset is held in the active state for a fixed period by a pair of resistors and a capacitor. Please check the reset requirements carefully
to ensure the reset circuit on the customers’ board meets all the reset timing requirements.
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