RX210のクロックを内蔵高速クロックに切り替えるプログラム

RX210のクロックを内蔵高速クロックに切り替えるプログラムです。ルネサスエレクトロニクスのサンプルコードを単純化したものです。 change_oscillation_HOCO()関数の引数でクロック周波数を変更できます。

1. /* RX210 cpuのクロックを内蔵高速クロックに切り替えるプログラム */
2.                                                                            
3.                                                                           
4. #include "iodefine.h"
5. #include <machine.h>
8. #define FREQ_32MHz (0x00) /* 32 MHz */
9. #define FREQ_36MHz (0x01) /* 36.864 MHz */
10. #define FREQ_40MHz (0x02) /* 40 MHz */
11. #define FREQ_50MHz (0x03) /* 50 MHz */
14. void change_oscillation_HOCO(unsigned char cpufreq) // <--引数にOSCの周波数を設定
15. {
16.     unsigned char reg_hocwtcr2;
17.     unsigned int i;
19.     cpufreq &= 0x03;
21.     if(cpufreq == FREQ_50MHz) {
22.         reg_hocwtcr2 = 0x03;        /* 50 MHz : 9216 cycles */
23.     } else {
24.         reg_hocwtcr2 = 0x02;        /* 32 MHz, 36.864 MHz, 40 MHz : 7168 cycles */
25.     }
27.     /* ---- Enable write protection ---- */
28.     /* PRCR - Protect Register
29.     b15:b8 PRKEY - PRC Key Code - A5h
30.                   (The write value should be A5h to permission writing PRCi bit)
31.     b7:b4 Reserved - The write value should be 0.
32.     b3 PRC3 - Protect Bit 3 - Write disabled
33.     b2 PRC2 - Protect Bit 2 - Write enabled
34.     b1 PRC1 - Protect Bit 1 - Write enabled
35.     b0 PRC0 - Protect Bit 0 - Write enabled */
36.     SYSTEM.PRCR.WORD = 0xA507;
38.     /* ---- Set the VRCR register ---- */
39.     SYSTEM.VRCR = 0x00;
41.     /* ---- Set the HOCO frequency ---- */
42.     /* HOCOCR2 - High-Speed On-Chip Oscillator Control Register 2
43.     b7:b2 Reserved - The write value should be 0.
44.     b1:b0 HCFRQ - HOCO Frequency Setting - 50 MHz */
45.     SYSTEM.HOCOCR2.BYTE = cpufreq;
47.     /* ---- Set wait time until the HOCO oscillator stabilizes ---- */
48.     /* HOCOWTCR2 - HOCO Wait Control Register 2
49.     b7:b4 Reserved - The write value should be 0.
50.     b3:b0 HSTS2 - HOCO Wait Time Select 2
51.                       - Wait time is 9216 cycles (approx. 184.32 us). */
52.     SYSTEM.HOCOWTCR2.BYTE = reg_hocwtcr2;
54.     //SYSTEM.SCKCR.BIT.BCK = 1;            //BCK　2分周
56.     /* ---- Operate the HOCO clock ---- */
57.     /* HOCOCR - High-Speed On-Chip Oscillator Control Register
58.     b7:b1 Reserved - The write value should be 0.
59.     b0 HCSTP - the HOCO is operating. */
60.     SYSTEM.HOCOCR.BYTE = 0x00;
62.     /* ---- Wait processing for the clock oscillation stabilization ---- */
63.     for(i=0;i<100;i++) nop();
65.     /* ---- Set the internal clock division ratio ---- */
66.     /* SCKCR - System Clock Control Register
67.     b31:b28 FCK - FlashIF Clock(FCLK) Select - divide-by-4
68.     b27:b24 ICK - System Clock (ICLK) Select - divide-by-2
69.     b23 PSTOP1 - BCLK Pin Output Control - disabled. (Fixed high)
70.     b22:b20 Reserved - The write value should be 0.
71.     b19:b16 BCK - External Bus Clock (BCLK) Select - divide-by-4
72.     b15:b12 Reserved - The write value should be 0001b.
73.     b10:b8 PCLKB - Peripheral Module Clock B(PCLKB) Select - divide-by-4
74.     b7:b4 Reserved - The write value should be 0001b.
75.     b3:b0 PCLKD - Peripheral Module Clock D(PCLKD) Select - divide-by-2 */
76.     SYSTEM.SCKCR.LONG = 0x10811110;    /* ICLK,PCLKD: no division PCLKB,BCLK,FCLK: divide-by-2 */
78.     while (0x10811110 != SYSTEM.SCKCR.LONG)
79.     {
80.          /* Confirm that the written value can be read correctly. */
81.     }
83.     /* ---- Set the BCLK pin output ---- */
84.     /* BCKCR - External Bus Clock Control Register
85.     b7:b1 Reserved - The write value should be 0.
86.     b0 BCLKDIV - BCLK Pin Output Select - divide-by-2 */
87.     SYSTEM.BCKCR.BYTE = 0x01;
89.     while (0x01 != SYSTEM.BCKCR.BYTE)
90.     {
91.         /* Confirm that the written value can be read correctly. */
92.     }
94.     /* ---- Set the internal clock source ---- */
95.     /* SCKCR3 - System Clock Control Register 3
96.     b15:b11 Reserved - The write value should be 0.
97.     b10:b8 CKSEL - Clock Source Select - PLL circuit is selected.
98.     b7:b1 Reserved - The write value should be 0. */
99.     SYSTEM.SCKCR3.WORD = 0x0100;
101.     while (0x0100 != SYSTEM.SCKCR3.WORD)
102.     {
103.         /* Confirm that the written value can be read correctly. */
104.     }
106.     /* ---- Disable write protection ---- */
107.     /* PRCR - Protect Register
108.     b15:b8 PRKEY - PRC Key Code - A5h
109.                   (The write value should be A5h to permission writing PRCi bit)
110.     b2 PRC2 - Protect Bit 2 - Write disabled
111.     b1 PRC1 - Protect Bit 1 - Write disabled
112.     b0 PRC0 - Protect Bit 0 - Write disabled */
113.     SYSTEM.PRCR.WORD = 0xA500;
115. }
118. void main(void)
119. {
120.     unsigned int i;
122.     change_oscillation_HOCO(FREQ_50MHz);            //クロック変更
124.     PORTC.PDR.BYTE = 0xFF;
125.     PORTC.PODR.BYTE = 0x00;
126.     PORTA.PDR.BYTE = 0xFF;
127.     PORTA.PODR.BYTE =0x00;
128.     PORTB.PDR.BYTE = 0xFF;
129.     PORTB.PODR.BYTE = 0xFF;
131.     while(1) {
132.         PORTC.PODR.BYTE = ~PORTC.PODR.BYTE;
133.         PORTA.PODR.BYTE = ~PORTA.PODR.BYTE;
134.         PORTB.PODR.BYTE = ~PORTB.PODR.BYTE;
135.         for(i=0;i<500000;i++) nop();
136.     }
138. }