Intel PXA255 PWM Duty Cycle Registers PWMDUTYn, PWMCTRLn Bit Definitions, 0x40B00000, Prescale

Models: PXA255

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System Integration Unit

Table 4-46. PWM_CTRLn Bit Definitions

Physical Address

PWM Control Registers

 

0x40B0_0000

System Integration Unit

(PWM_CTRL0, PWM_CTRL1)

0x40C0_0000

 

 

 

Bit 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7

reserved

Reset 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

6

5

4

3

2

1

0

_SD

 

PRESCALE

 

 

 

PWM

 

 

 

 

 

 

 

 

0

0

0

0

0

0

0

Bits

Name

Description

 

 

 

<31:7>

reserved

 

 

 

 

 

PWMn Shutdown Method:

<6>

PWM_SD

0 – Graceful shutdown of PWMn when the clock enable bit in the CKEN register is

cleared.

 

 

 

 

1 – Abrupt shutdown of PWMn when the clock enable bit in the CKEN register is cleared.

 

 

 

 

 

PWMn Prescale Divisor.

<5:0>

PRESCALE

Determines the frequency of the PWM module clock (in terms of the 3.86 MHz clock)

 

 

PSCLK_PWMn = 3.6864 MHz / (PWM_CTRL[PRESCALE] + 1)

 

 

 

4.5.2.2PWM Duty Cycle Registers (PWM_DUTYn)

The PWM_DUTYn, shown in Table 4-47, contains two fields:

FDCYCLE

DCYCLE

The FDCYCLE bit determines whether or not PWM_OUTn is a function of the DCYCLE bits in the PWM_DUTYn register or is set high. When the FDCYCLE bit is cleared low (normal operation), the output waveform of PWM_OUTn is cyclic, with PWM_OUTn being high for the number of PSCLK_PWMn periods equal to DCYCLE.

If FDCYCLE=0x0 and DCYCLE=0x0, PWM_OUTn is set low and does not toggle.

Note: If FDCYCLE is 0b1, PWM_OUTn is high for the entire period and is not influenced by the value programmed in the DCYCLE bits.

Intel® PXA255 Processor Developer’s Manual

4-41

Page 145
Image 145
Intel PXA255 manual PWM Duty Cycle Registers PWMDUTYn, PWMCTRLn Bit Definitions, 0x40B00000, Prescale