ht82a836r Holtek Semiconductor Inc., ht82a836r Datasheet - Page 52

• Manufacturer Part Number: ht82a836r
• Description: Usb Audio Mcu
• Manufacturer: Holtek Semiconductor Inc.

7+1 PWM Mode
Each full PWM cycle, as it is controlled by an 8-bit PWM
register, has 256 clock periods. However, in the 7+1
PWM mode, each PWM cycle is subdivided into two indi-
vidual sub-cycles known as modulation cycle 0 ~ modula-
tion cycle 1, denoted as i in the table. Each one of these
two sub-cycles contains 128 clock cycles. In this mode, a
modulation frequency increase of two is achieved. The
8-bit PWM register value, which represents the overall
duty cycle of the PWM waveform, is divided into two
groups. The first group which consists of bit1~bit7 is de-
noted here as the DC value. The second group which
consists of bit0 is known as the AC value. In the 7+1
PWM mode, the duty cycle value of each of the two mod-
ulation sub-cycles is shown in the following table.
Rev. 1.00
Pulse Width Modulation Registers for (6+2) PWM Mode
Pulse Width Modulation Registers for (7+1) PWM Mode
(7+1) PWM Mode Output Waveform
52
The following diagram illustrates the waveforms associ-
ated with the 7+1 mode of PWM operation. It is impor-
tant to note how the single PWM cycle is subdivided into
2 individual modulation cycles, numbered from 0~1 and
how the AC value is related to the PWM value in the 7+1
PWM Mode.
Modulation cycle i
Parameter
(i=0~1)
7+1 Mode Modulation Cycle Values
AC (0~1)
i<AC
i AC
HT82A836R
(Duty Cycle)
March 20, 2008
DC+1
128
128
DC
DC