Renesas RA Series Quick Design Guide

Renesas RA Family RA4 Quick Design Guide
R01AN5988EU0100 Rev.1.00 Page 16 of 51
Jul.21.21
Table 7. RA4 Oscillators
Oscillator
Input Source
Frequency
Primary Uses
Main clock
External
crystal/resonator
-or-
 External clock
8 MHz to 24 MHz
*3
Up to 24 MHz
*3
PLL input, PLL2 input
*1
, main
system clock, CLKOUT, CAN
clock, CAC clock, LCD clock
*2
Sub-clock
(SOSC)
External
crystal/resonator
32.768 kHz
Real-time clock, main system
clock in low power modes,
CLKOUT, AGT clock, CAC clock,
Real-time clock, LCD clock
*2
High-speed on-chip
(HOCO)
On-chip oscillator
16/18/20 MHz
*4
PLL input
*1
, main system clock,
CLKOUT, CAC clock, LCD
clock
*2
, USB clock
*2
Middle-speed on-chip
(MOCO)
On-chip oscillator
8 MHz
Main system clock at startup,
CLKOUT, CAC clock
Low-speed on-chip
(LOCO)
On-chip oscillator
32.768 kHz
Main system clock in low power
modes & during main oscillator
stop detection, Systick timer
*1
,
AGT clock, CLKOUT, CAC clock,
Real-time clock
Independent
Watchdog (IWDT)
On-chip oscillator
15 kHz
Independent watchdog timer
clock, CAC clock
Note 1. On Arm Cortex-M33 devices
2. On Arm Cortex-M4 devices
3. On Arm Cortex-M4 devices, the main clock input frequency range using an external crystal
resonator or external clock source is 1 MHz to 20 MHz. The maximum input frequency for an
external clock or external crystal resonator may be limited to 8 MHz, 4 MHz, or 1 MHz, depending
on the supply voltage to the MCU.
4. On Arm Cortex-M4 devices, the HOCO frequency options are 24/32/48/64 MHz.
5.1 Reset Conditions
After reset, RA4 MCUs begin running with the middle-speed on-chip oscillator (MOCO) as the main clock
source. At reset, the main oscillator and the PLL are off by default. The HOCO and IWDT may be on or off
depending on the settings in the option setting memory (see section 4).
5.2 Clock Frequency Requirements
Minimum and maximum clock oscillation frequencies are shown in the tables below. Details can be found in
the “Overview” section of the “Clock Generation Circuit” chapter in the MCU Hardware User’s Manual,
including external and internal clock source specifications. Additional details can be found in the “AC
Characteristics” section of the “Electrical Characteristics” chapter in the MCU Hardware User’s Manual.
Table 8. Frequency Range for Arm Cortex-M4 MCU Internal Clocks
ICLK
PCLKA
PCLKB
PCLKC
PCLKD
Maximum Frequency [MHz]
48
48
32
64
64
Minimum Frequency [MHz]





FCLK
1
UCLK
CANCLK
SLCDC
Maximum Frequency [MHz]
32
48
20
64
Minimum Frequency [MHz]
1
48
1

Note 1. The FCLK must run at a frequency of at least 4 MHz when writing or erasing ROM or data flash.

Renesas RA Series Specifications

General

Brand	Renesas
Model	RA Series
Category	Microcontrollers
Language	English