Read The User-Defined Internal Irc Frequency (Read From Ram) - STC micro STC8A8K64D4 Series Reference Manual

STC8A8K64D4 Series Manual

7.5.12 Read the User-defined internal IRC Frequency (Read from RAM)

C language code
//Operating frequency for test is 11.0592MHz
#include "reg51.h"
#include "intrins.h"
#define CLKDIV
sfr P_SW2
sfr IRTRIM
sfr P1M1
sfr P1M0
sfr P0M1
sfr P0M0
sfr P2M1
sfr P2M0
sfr P3M1
sfr P3M0
sfr P4M1
sfr P4M0
sfr P5M1
sfr P5M0
char *IRC22M;
char *IRC24M;
void main()
{
P0M0 = 0x00;
P0M1 = 0x00;
P1M0 = 0x00;
P1M1 = 0x00;
P2M0 = 0x00;
P2M1 = 0x00;
P3M0 = 0x00;
P3M1 = 0x00;
P4M0 = 0x00;
P4M1 = 0x00;
P5M0 = 0x00;
P5M1 = 0x00;
IRC22M = (char idata *)0xfa;
IRC24M = (char idata *) 0xfb;
// IRCCR = *IRC22M;
IRCCR = *IRC24M;
P_SW2 = 0x80;
CLKDIV = 0;
P_SW2 = 0x00;
while (1);
}
Assembly code
;Operating frequency for test is 11.0592MHz
(*(unsigned char volatile xdata *)0xfe01)
= 0xba;
= 0x9f;
= 0x91;
= 0x92;
= 0x93;
= 0x94;
= 0x95;
= 0x96;
= 0xb1;
= 0xb2;
= 0xb3;
= 0xb4;
= 0xc9;
= 0xca;
//Load 22.1184MHz IRC parameters
//Load 24MHz IRC parameters
//No division to main clock
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