topic Re: LPC1114 with 50MHz using 12MHz IRC in LPCXpresso IDE

LPC1114 with 50MHz using 12MHz IRC

lpcware — Thu, 16 Jun 2016 02:01:57 GMT

Content originally posted in LPCWare by antodonne on Wed Feb 22 06:38:17 MST 2012
Hello,

I got an issue to reach this frequency using the PLL.
Someone got information or sample code to explain how I can do that?
Thank you and best regards.

Antoine

Re: LPC1114 with 50MHz using 12MHz IRC

lpcware — Thu, 16 Jun 2016 02:01:58 GMT

Content originally posted in LPCWare by Ex-Zero on Wed Feb 22 07:13:46 MST 2012
You're kidding?

As described in User manual UM10398, Chapter 3.11.4.1:

Quote:

2. Calculate M to obtain the desired output frequency FCLKOUT with
M = FCLKOUT / FCLKIN.

So that's not possible with 12MHz :(

Re: LPC1114 with 50MHz using 12MHz IRC

lpcware — Thu, 16 Jun 2016 02:01:58 GMT

Content originally posted in LPCWare by ArneB on Wed Feb 22 08:42:16 MST 2012
...but you are able to achieve 48MHz with P=2 (PSEL=1) and M=4 (MSEL=3), see table 45, page 45 of the user manual.

Re: LPC1114 with 50MHz using 12MHz IRC

lpcware — Thu, 16 Jun 2016 02:01:59 GMT

Content originally posted in LPCWare by NXP_Europe on Wed Feb 22 10:54:05 MST 2012
Hello antodonne,

When choosing a frequency, it should be times an integer value (M) of the basic clock-oscillator (e.g. 12 MHz IRC).

Like Zero and Arneb said, in Table 45. in UM10398, is shown which values are possible.

FCLKOUT = M * FCLKIN ... (< 100 MHz)
FCCO = FCLOUT / (2 * P) ... (> 156 MHz and < 320 MHz)

Example 1.: your choice would be M = 9, then FCLKOUT = 108 MHz, which is out of spec (< 100 MHz).

Example 2.: Suppose M=4 and P=1, FCLKOUT = M * FCLKIN = 4 * 12 MHz = 48 MHz
then FCCO = 2 * P * FCLKOUT = 2 * 1 * 48 = 96 MHz
Not possible ... because: 156 MHz < FCCO < 320 MHz

In Fig 5. a figure is shown how the total fitts together.

Re: LPC1114 with 50MHz using 12MHz IRC

lpcware — Thu, 16 Jun 2016 02:02:00 GMT

Content originally posted in LPCWare by Ex-Zero on Wed Feb 22 11:08:23 MST 2012

Quote: NXP_Europe

FCLKOUT = M * FCLKIN ... ([B][COLOR=Red]< 100 MHz[/COLOR][/B])

Really funny :) It's carnival time :rolleyes:

Re: LPC1114 with 50MHz using 12MHz IRC

lpcware — Thu, 16 Jun 2016 02:02:00 GMT

Content originally posted in LPCWare by vostro1000 on Wed Feb 22 15:07:13 MST 2012
Carnival is over :)

Re: LPC1114 with 50MHz using 12MHz IRC

lpcware — Thu, 16 Jun 2016 02:02:01 GMT

Content originally posted in LPCWare by serge on Thu Feb 23 00:27:02 MST 2012
Rosenmontag may be over for zero :D but in Belgium we have carnival till the end of march...:p

Re: LPC1114 with 50MHz using 12MHz IRC

lpcware — Thu, 16 Jun 2016 02:02:01 GMT

Content originally posted in LPCWare by wama on Thu Feb 23 04:38:27 MST 2012
Do I have to set this values in the function "SystemInit()"?

Which setting are necessary to debug with 24Mhz? I use LPC-Link for debugging.

Re: LPC1114 with 50MHz using 12MHz IRC

lpcware — Thu, 16 Jun 2016 02:02:02 GMT

Content originally posted in LPCWare by Ex-Zero on Thu Feb 23 04:54:36 MST 2012
In system_LPC11xx.c of your CMSIS library you can find the main settings:

...
#define CLOCK_SETUP           1
#define SYSCLK_SETUP          1
#define SYSOSC_SETUP          1
#define SYSOSCCTRL_Val        0x00000000
#define WDTOSC_SETUP          0
#define WDTOSCCTRL_Val        0x000000A0
#define SYSPLLCLKSEL_Val      0x00000001
#define SYSPLL_SETUP          1
[B][COLOR=Red]#define SYSPLLCTRL_Val        0x00000023[/COLOR][/B]
#define MAINCLKSEL_Val        0x00000003
#define SYSAHBCLKDIV_Val      0x00000001
#define AHBCLKCTRL_Val        0x0001005F
#define SSP0CLKDIV_Val        0x00000001
#define UARTCLKDIV_Val        0x00000001
#define SSP1CLKDIV_Val        0x00000001
...

In UM10398 chapter 3.5.3 'System PLL control register' and chapter 3.11.4.1 'Normal mode' you can find some formulas and table 45, as mentioned in this post already

Re: LPC1114 with 50MHz using 12MHz IRC

lpcware — Thu, 16 Jun 2016 02:02:02 GMT

Content originally posted in LPCWare by wama on Thu Feb 23 05:35:56 MST 2012
Ok, thank you.
I already found this defines in system_LPC11xx.h but forgot to set MAINCLK_SEL_Val :rolleyes:.

Now the mcu is running at 24Mhz. Is there anything to do in debug mode?
[SIZE=2][/SIZE]

Re: LPC1114 with 50MHz using 12MHz IRC

lpcware — Thu, 16 Jun 2016 02:02:03 GMT

Content originally posted in LPCWare by Ex-Zero on Thu Feb 23 05:45:17 MST 2012

Quote: mawa
Now the mcu is running at 24Mhz. Is there anything to do in debug mode?

No, why do you ask? LPC-Link is debugging your mcu, regardless of 24 or 48 MHz :)

Re: LPC1114 with 50MHz using 12MHz IRC

lpcware — Thu, 16 Jun 2016 02:02:03 GMT

Content originally posted in LPCWare by wama on Thu Feb 23 06:29:08 MST 2012

Quote: Zero
No, why do you ask? LPC-Link is debugging your mcu, regardless of 24 or 48 MHz :)

Because there are some settings in the debug configuration.
For example there is a input field to set XTAL frequency and PLL value.

Re: LPC1114 with 50MHz using 12MHz IRC

lpcware — Thu, 16 Jun 2016 02:02:04 GMT

Content originally posted in LPCWare by Ex-Zero on Thu Feb 23 09:22:01 MST 2012

Quote: mawa
Because there are some settings in the debug configuration.
For example there is a input field to set XTAL frequency and PLL value.

There's no need to change settings from default (= no entry) :)