Texas Instruments MSC1210 - Manual (Page 134)

PWM Generator
11-10
Table 11−4. Configuring the PWM for Tone Generation with PWM Idling
Stmt ‘C’ Source Code Assembly Source Code
1 // PWM PUBLIC main
RSEG ???main?PWM
2 #include
3 #define OneUsConst (2−1)
4 sbit p33=p3^3;
5 void main(void) Main:
6 {
7 PDCON &= 0xED; // turn on tone gen & sys timer ANL PDCON,#0Edh
8 USEC = OneUsConst; MOV USEC,#01h
9 P33 = 1; // turn on P3.3 SETB p33
10 PWMCON = 0; // select PWMPeriod MOV PWMCON,#00h
11 PWM = 5; // Set PWMPeriod MOV PWMHI,#00h
MOV PWMLOW,#05h
12 PWMCON = 0x10; // select PWMDuty MOV PWMCON,#10h
13 PWM = 0; // Set PWMDuty MOV PWMHI,#00h
MOV PWMLOW,#04h
14 PWMCON = 0x09; // Enable PWM MOV PWMCON,#09h
15 for(i=0; i < 10; i++); MOV R7,#00h
Loop:
INC R7
CJNE R7,#0Ah,Loop
16 PWMCON = 0x10; // select PWMDuty MOV PWMCON,#10h
17 PWM = 4; // Set PWMDuty MOV PWMHI,#00h
MOV PWMLOW,#04h
18 PWMCON = 0x09; // Enable PWM MOV PWMCON,#09h
19 while(1) {} SJMP $
20 }
Table 11−5. Statement Explanations
Statement # Explanation
1−12 Same as previous program in section 11.3.1.
13 Sets PWM Duty to 0, thereby configuring the PWM tone generator for idle mode.
14 Enables PWM. The PWM is enabled, but is in idle mode due to the fact that PWM Duty is 0.
15 This loops for an arbitrary number of instructions.
16−20 Same as statements 12 to 16 in previous program in section 11.3.2.