Renesas RX230, Руководство пользователя, Страница: 10 / 25

RX230 Group, RX231 Group Initial Settings and Usage Procedure of RTC Battery Backup Function
R01AN4831EJ0100 Rev.1.00 Page 10 of 23
Aug.20.19
2.3 Clock Settings
Table 2.2, Clock Settings, lists the clocks used by the sample program.
Table 2.2 Clock Settings
Name
Operating
Frequency Clock
Source Frequency
Dividing Ratio Multiplication
Factor
Main clock 8 MHz Implemented
externally
⎯ ⎯
Subclock 32.768 kHz Implemented
externally
⎯ ⎯
High-speed on-chip oscillator (HOCO) Stopped
⎯ ⎯ ⎯
Low-speed on-chip oscillator (LOCO) Stopped
⎯ ⎯ ⎯
IWDT on-chip oscillator Stopped
⎯ ⎯ ⎯
PLL circuit 54 MHz Main clock 2 13.5
USB clock 48 MHz Main clock 2 12
System clock (ICLK) 54 MHz PLL 1
⎯
Peripheral clock A (PCLKA) 54 MHz PLL 1
⎯
Peripheral clock B (PCLKB) 27 MHz PLL 2
⎯
Peripheral clock D (PCLKD) 27 MHz PLL 2
⎯
Flash interface clock (FCLK) 27 MHz PLL 2
⎯
2.4 LCD Panel
The LCD panel (Pmod specification) included with the RSK is used.
2.5 Hardware Modifications
To confirm the operation of the sample program, modifications were made to the RSK to enable battery
backup operation.
2.5.1 VBATT Connection
The RX231 RSK board is provided with jumper J10 to allow confirming operation of the battery backup
function. However, jumper J10 is not mounted on the board when it is shipped from the factory and VBATT
pin is connected to VCC by resistor R86. It is therefore necessary to make the following modifications.
1. Remove resistor R86.
2. Solder resistor R85 to the board.
3. Solder a pin header (two-pin) to the board in the jumper J10 location.
For reference when performing modifications, see Figure 2.2, Excerpt from RSKRX231
User’s Manual, and
Figure 2.3, VBATT Circuit Detail Excerpted from RSKRX231 CPU Board Schematics.