topic max MIPS in ColdFire/68K Microcontrollers and Processors

Code: #include /* for EnableInterrupts ma...

gbaars — Thu, 29 Oct 2020 09:21:04 GMT

Code:

#include <hidef.h> /* for EnableInterrupts macro */#include "derivative.h" /* include peripheral declarations */dword a;void main(void) {  /* Disable Watchdog */  SOPT1 &= 0b00111111;     /* set FLL division */  MCGC4 &= 0b11011100;  MCGC4 |= 0b00100001;        RGPIO_ENB = 0xffff;  RGPIO_DIR = 0xffff;        while (1){      for (a=0;a<10000;a++) {    }    RGPIO_TOG = 0xffff;      } }

With this on an RGPIO pin only 7.5 ms per loop is measured.

The for loop translates into 7 asm.inst. The average speed

is 10 MIPS only. How can it go faster??

err. Topic of message is "maximum MIPS on MCF51JM128...

gbaars — Sun, 13 Jul 2008 01:16:00 GMT

err. Topic of message is "maximum MIPS on MCF51JM128"

Re: err. Topic of message is "maximum MIPS on MCF51JM128...

JimDon — Sun, 13 Jul 2008 04:05:38 GMT

My advise is to use processor expert to be sure you have set the clock to the maximum.
Chances are you do not have the clock set as high as it will go.

max MIPS

gbaars — Mon, 14 Jul 2008 01:02:01 GMT

After trying the processor expert

it seems not available for the 51JM128 (only for QE).

All MGC settings to default (it should

run at 32..40 MHz) (internal refclk x 1024).

After starting the debugger (via BDM to external target)

a message appears (in the command window):

Reset command file correctly executed.
FP: FLASH parameters loaded for MCF51JM128_V0_4 from C:\Program Files\Freescale\CodeWarrior for Microcontrollers V6.1\prog\FPP\mcu7003.fpp

      MCU clock speed: 4541000 Hz
Block Module Name      Address Range   Status
   0 FLASH                0 - FFFF   Programmed - Unselected

This sets the MCU clk to 4.5 Mhz, why does it do that??

(the goal is to achieve 50 Mhz mcuclk and 25 mhz busclk).