S5PV210 时钟

ゞ浴缸里的玫瑰 2022-06-09 12:12 239阅读 0赞

**CLOCK DOMAINS** 时钟域

> S5PV210 consists of three clock domains, namely, main system (MSYS), display system (DSYS), and peripheral system (PSYS)

![1][]

**时钟源**  
`外部焊接:`

> 1.XRTCXTI：实时时钟  
> 2.XXTI：CPU时钟  
> 3.XUSBXTI：USB时钟  
> 4.XHDMIXTI：HDMI时钟

![1][1 1]

`CMU典型应用:`

> 1.MSYS clock domain uses APLL (that is, ARMCLK, HCLK\_MSYS, and PCLK\_MSYS)  
> 2.DSYS and PSYS clock domain (that is, HCLK\_DSYS, HCLK\_PSYS, PCLK\_DSYS, and PCLK\_PSYS) and other peripheral clocks (that is, audio IPs, SPI, and so on) use MPLL and EPLL  
> 3.Video clocks uses VPLL

![1][1 2]

**时钟关系**

MSYS clock domain
    − freq(ARMCLK) = freq(MOUT_MSYS) / n, where n = 1 ~ 8
    − freq(HCLK_MSYS) = freq(ARMCLK) / n, where n = 1 ~ 8 //高速
    − freq(PCLK_MSYS) = freq(HCLK_MSYS) / n, where n = 1 ~ 8 //低速
    − freq(HCLK_IMEM) = freq(HCLK_MSYS) / 2 //内存
    • DSYS clock domain
    − freq(HCLK_DSYS) = freq(MOUT_DSYS) / n, where n = 1 ~ 16
    − freq(PCLK_DSYS) = freq(HCLK_DSYS) / n, where n = 1 ~ 8
    • PSYS clock domain
    − freq(HCLK_PSYS) = freq(MOUT_PSYS) / n, where n = 1 ~ 16
    − freq(PCLK_PSYS) = freq(HCLK_PSYS) / n, where n = 1 ~ 8
    − freq(SCLK_ONENAND) = freq(HCLK_PSYS) / n, where n = 1 ~ 8 //nand

**PLL** 锁相环

> 1.APLL can drive MSYS domain and DSYS domain  
> 2.MPLL can drive MSYS domain and DSYS domain  
> 3.EPLL is mainly used to generate audio clock  
> 4.VPLL is mainly used to generate video system operating clock

**CLK\_SRC0, R/W, Address = 0xE010\_0200**  
PLL选择，通过设置相应的位  
![1][1 3]

**倍频**  
以APLL举例

`APLL_CON0, R/W, Address = 0xE010_0100`  
![1][1 4]

> FOUT = MDIV \* FIN / (PDIV \* 2^(SDIV-1))
> 
> PDIV: 1 ≤ PDIV ≤ 63  
> MDIV: 16 ≤ MDIV ≤ 1023  
> SDIV: 0 ≤ SDIV ≤ 5

`常用参考值`  
![1][1 5]

`倍频到1G`  
输入频率，默认24M

> FOUT = 125 \* 24 / (3 \* 2^(1-1)) = 1000

[1]: /images/20220609/fc8c448004f74631bc252260be316694.png
[1 1]: /images/20220609/fd8fd46ee76d4706a78aaced6c3ee3d8.png
[1 2]: /images/20220609/63cd6f940e3144199f29542287d90d4a.png
[1 3]: /images/20220609/6eab6e70163e498495fc5fa470d3bf78.png
[1 4]: /images/20220609/fa67ea7a0731474c9e12d087d266d31d.png
[1 5]: /images/20220609/eb0712d2d8a543ab93d88554fb4765f3.png