LPCXpresso IDEのトピックLPCXpresso LPC11C24 clock generation

LPCXpresso LPC11C24 clock generation

lpcware — Thu, 16 Jun 2016 13:58:52 GMT

Content originally posted in LPCWare by dlchnr on Tue Jul 26 02:29:21 MST 2011
Hello,
I'm working with a LPC11C24 LPCXpresso board and try to understand
the "can_onchip" example.
Now I've a problem to understand the clock generation.
The used CAN_BTR value (0x00001C57UL) and a measurement at
PIO0_1 (CLKOUT) tell me, the LPC11C24 will run with 48MHz.
"SYSPLLCTRL_Val" is defined as 0x00000023 in "system_LPC11xx.h".
The "3" will lead to a MSEL value of 4, which fits to the oscillator input
of 12MHz placed on the board according to the schematic (48MHz / 4 = 12MHz).
But the PSEL value of "2" will result in a post divider ratio P of 4 with a
division ratio of 8 ("division ratio is 2 x P"), which leads to a FCCO
(Frequency of the Current Controlled Oscillator) of 384MHz.
That's out of the 156 to 320 MHz range required!?
Where is error in my chain of thought?
Thx, dlchnr

http://www.dict.cc/englisch-deutsch/chain+of+thought.html

Re: LPCXpresso LPC11C24 clock generation

lpcware — Thu, 16 Jun 2016 14:00:46 GMT

Content originally posted in LPCWare by Ex-Zero on Tue Jul 26 02:56:17 MST 2011
Try:

MSEL bit 0:4
PSEL bit 5:6

then, of course 0x023 results in:

MSEL = 3
PSEL = 1 :smileyshocked:

Re: LPCXpresso LPC11C24 clock generation

lpcware — Thu, 16 Jun 2016 14:01:05 GMT

Content originally posted in LPCWare by dlchnr on Tue Jul 26 03:16:28 MST 2011

Quote: Zero

PSEL = 1 :eek:

I figured that I make a stupid mistake :-)

thx, dlchnr