8. Special I/O Functions
8.7 PWM output function
Function
This function is used to output a variable duty cycle pulse train. The controllable duty cycle is 0 to 100 % (1 % units).
ON duty | 50% | 70% | 60% |
PWM
T | T | T | T = Pulse cycle |
The PWM output is enabled when the pulse enable flag is ON. While the pulse enable flag is ON, the duty cycle (ON duty) can be changed by changing the duty setting value (0 to 100).
The frequency setting is available in the range of 50 to 5000 Hz (1 Hz units) before turning ON the pulse enable flag. The frequency changing is not allowed while the pulse enable is ON.
Note that the minimum ON/OFF pulse duration is 100 ms. Therefore, the controllable ON duty range is limited depending on the frequency setting as follows. If the ON duty setting value is not available (within 0 to 100), the pulse width error flag comes ON. (PWM output operation is continued but the duty cycle is not guaranteed)
Frequency | Cycle time |
| Available ON duty |
50 - 100 Hz | 20 - 10 ms | 0 to 100 % | |
200 Hz | 5 ms | 0, | 2 to 98, 100 % |
1000 Hz | 1 ms | 0, | 10 to 90, 100 % |
5000 Hz | 200 ms | 0, 50, 100 % | |
Related registers
SW26: Function selection. Refer to section 8.1.
Function | Register/ | Remarks |
| device |
|
PWM pulse | Y020 |
|
Pulse enable flag | S270 | Output is enabled when ON |
Frequency setting register | SW28 | Data range: 50 to 5000 |
ON duty setting register | SW29 | Data range: 0 to 100 |
Pulse width error flag | S26D | ON at error (reset OFF automatically) |
ON duty setting error flag | S26E | ON at error (reset OFF automatically) |
Frequency setting error flag | S26F | ON at error (reset OFF automatically) |
Note) If the setting value of SW28 or SW29 is out of the allowable range, the frequency setting error flag (S26F) or the ON duty setting error flag (S26E) comes ON. (PWM output operation is continued with previous ON duty setting)
Basic Hardware and Function 285
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