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i.MX25 3-Stack board WinCE BSP PWM Problem

Question asked by Zhou Lishan on Sep 17, 2013
Latest reply on Oct 7, 2013 by Bio_TICFSL

I use WinCE BSP with the i.MX25 3-Stack board.

The PWM used to drive the backlight on the i.MX25 3-Stack board is the PWM function within LCD Controller

instead of the PWM referenced in Chapter 37 of i.MX25 Reference Manual.

As the frequency of PWM within LCD Controller is too high(200KHz) or too low(110Hz) (We need 300Hz).

We use the PWM referenced in Chapter 37 of i.MX25 Reference Manual. We Set the PWM output frequency with

200Hz, used IPG_CLK32K as the source clock, it work prefect. But when We Set the GPIO3 GPIO[19] output high,

the PWM output a Waveform with random Duty. The registers of PWM seems set right (See Below), Can Anyone help

me ?

 

INFO: PWM REG Value

CR : 00030001

SR : 00000001

IR : 00000000

SAR: 0000001e

PR : 000000a0

CNR: 00000000


GPIO3_GPIO[19]--->IOMUXC_SW_MUX_CTL_PAD_POWER_FAIL = 0xb0

GPIO3_GPIO[19]--->IOMUXC_SW_MUX_CTL_PIN_POWER_FAIL = 0x05

 

PWM1--->IOMUXC_SW_MUX_CTL_PAD_PWM = 0xa0

PWM1--->IOMUXC_SW_MUX_CTL_PIN_PWM = 0x0

 

PWM4--->IOMUXC_SW_MUX_CTL_PAD_CONTRAST = 0xc0

PWM4->IOMUXC_SW_MUX_CTL_PIN_CONTRAST = 0x4

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