Aidan Walton / Mbed 2 deprecated ClockControl

Updated functions to deal with USB clocking. (PPL1) See http://www.nxp.com/documents/user_manual/UM10360.pdf Section 4.6 & 4.7.3

Dependencies:   mbed

Fork of ClockControl by Michael Wei

ClockControl/ClockControl.cpp@2:ab85c20317b5, 2016-09-12 (annotated)

Committer:
aidan1971
Date:
Mon Sep 12 13:11:32 2016 +0000
Revision:
2:ab85c20317b5
Parent:
1:8b04bd33c7cd 
Added comments and command to change TIMER3 prescaler

Who changed what in which revision?

UserRevisionLine numberNew contents of line
no2chem 0:b5d3bd64d2dc 1 #include "ClockControl.h"
no2chem 0:b5d3bd64d2dc 2
no2chem 0:b5d3bd64d2dc 3 void setPLL0Frequency(unsigned char clkSrc, unsigned short M, unsigned char N)
no2chem 0:b5d3bd64d2dc 4 {
no2chem 0:b5d3bd64d2dc 5 LPC_SC->CLKSRCSEL = clkSrc;
no2chem 0:b5d3bd64d2dc 6 LPC_SC->PLL0CFG = (((unsigned int)N-1) << 16) | M-1;
no2chem 0:b5d3bd64d2dc 7 LPC_SC->PLL0CON = 0x01;
no2chem 0:b5d3bd64d2dc 8 LPC_SC->PLL0FEED = 0xAA;
no2chem 0:b5d3bd64d2dc 9 LPC_SC->PLL0FEED = 0x55;
no2chem 0:b5d3bd64d2dc 10 while (!(LPC_SC->PLL0STAT & (1<<26)));
no2chem 0:b5d3bd64d2dc 11
no2chem 0:b5d3bd64d2dc 12 LPC_SC->PLL0CON = 0x03;
no2chem 0:b5d3bd64d2dc 13 LPC_SC->PLL0FEED = 0xAA;
no2chem 0:b5d3bd64d2dc 14 LPC_SC->PLL0FEED = 0x55;
no2chem 0:b5d3bd64d2dc 15 }
no2chem 0:b5d3bd64d2dc 16
aidan1971 1:8b04bd33c7cd 17 void setPLL1Frequency(unsigned short M, unsigned char P)
no2chem 0:b5d3bd64d2dc 18 {
aidan1971 1:8b04bd33c7cd 19 LPC_SC->PLL1CFG = (((unsigned int)P-1) << 16) | M-1;
no2chem 0:b5d3bd64d2dc 20 LPC_SC->PLL1CON = 0x01;
no2chem 0:b5d3bd64d2dc 21 LPC_SC->PLL1FEED = 0xAA;
no2chem 0:b5d3bd64d2dc 22 LPC_SC->PLL1FEED = 0x55;
aidan1971 1:8b04bd33c7cd 23 while (!(LPC_SC->PLL1STAT & (1<<10)));
no2chem 0:b5d3bd64d2dc 24
no2chem 0:b5d3bd64d2dc 25 LPC_SC->PLL1CON = 0x03;
no2chem 0:b5d3bd64d2dc 26 LPC_SC->PLL1FEED = 0xAA;
no2chem 0:b5d3bd64d2dc 27 LPC_SC->PLL1FEED = 0x55;
no2chem 0:b5d3bd64d2dc 28 }
no2chem 0:b5d3bd64d2dc 29
aidan1971 1:8b04bd33c7cd 30 unsigned int setSystemFrequency( unsigned char USBclkDivider, unsigned char clkDivider, unsigned char clkSrc, unsigned short M, unsigned char N)
no2chem 0:b5d3bd64d2dc 31 {
no2chem 0:b5d3bd64d2dc 32 setPLL0Frequency(clkSrc, M, N);
no2chem 0:b5d3bd64d2dc 33 LPC_SC->CCLKCFG = clkDivider - 1;
aidan1971 1:8b04bd33c7cd 34 LPC_SC->USBCLKCFG = USBclkDivider - 1;
aidan1971 2:ab85c20317b5 35 // Default "PCLK_peripheral = CCLK/4".
aidan1971 1:8b04bd33c7cd 36 // If System Clock is changed from default, TIMER3 changes with it. eg 96Mhz System clock TIMER3 1uS = 1uS. System Clock = 120Mhz. 1uS will actually become 0.8uS.
aidan1971 2:ab85c20317b5 37 //LPC_SC->PCLKSEL1 = 1 << 14; // Sets divider for TIMER3 to CCLK / 1.
aidan1971 2:ab85c20317b5 38 //LPC_TIM3->PR = 74; // Sets prescaler for TIMER3 counter. (Default at 96Mhz and PCLKSEL = 0 (ie. CCLK/4) is 23) Therefore if we set PCLKSEL = CCLK/1 and scale down by (23*4) * 96Mhz/120hz = 73.6. Not perfect...but it works
no2chem 0:b5d3bd64d2dc 39 SystemCoreClockUpdate();
no2chem 0:b5d3bd64d2dc 40 return SystemCoreClock;
aidan1971 1:8b04bd33c7cd 41 }
aidan1971 1:8b04bd33c7cd 42
aidan1971 1:8b04bd33c7cd 43 void setPPL1forUSB(unsigned short M, unsigned char P)
aidan1971 1:8b04bd33c7cd 44 {
aidan1971 1:8b04bd33c7cd 45 setPLL1Frequency(M, P); // Drive USB subsystem from PLL1
no2chem 0:b5d3bd64d2dc 46 }