Content originally posted in LPCWare by mirfan on Wed Nov 28 05:13:06 MST 2012 Hi,
I am working at Mentor Graphics and hoping to add Power Management support to LPC4350. I am using a HITEX board. My demo application switches the core at different operating frequencies (12MHz,48MHz, 96MHz and 204MHz) after every 2 seconds. The issue I am facing is somewhat already known i.e. Core crashes if its clock is ramped up from below 90MHz to 204MHz. The issue does not appear every time I make a switch. Right now I get a crash after around 40 mins. During this time the core is continuously moved to all the other operating frequencies without an issue but eventually it crashes. I have also put in the work around of moving the core to 204MHz in multiple steps using the FASTBOOT example as a reference. The code is running from internal SRAM.
Content originally posted in LPCWare by bjorn1989 on Fri Dec 20 08:15:09 MST 2013 Dear Mirfan,
how do you change the core frequency, I also want to set the Core clock to 204MHz. I am using the MCB4300 board but the core is the same. I know it must be done in steps, I use the PLL1_CTRL register to setup the dividers, XTAL as input ect.
Content originally posted in LPCWare by nxp21346 on Wed Nov 28 14:28:58 MST 2012 Hi!
To ramp up the clock frequency from low frequencies (< 90 MHz), you must increase the core clock BASE_M4_CLK in two steps from low frequencies to mid-range frequencies (90 MHz to 110 MHz) and subsequently from mid-level frequencies to high frequencies (up to 204 MHz). This is in the User's Manual in the CGU section.