AM335X: Pin usage questions

Meng jeffrey

One of the AM335 series I am using now has a question to ask for help;

Are the V9 pins and C12 pins of this chip different from the control of the LCD control?(back light output high level, backlight output low level)

Note: backlight will need to be delayed after starting.

over 8 years ago

0 Biser Gatchev-XID over 8 years ago

TI__Guru**** 393215 points

Please post exact part number and software being used.

0 Meng jeffrey over 8 years ago in reply to Biser Gatchev-XID

Expert 2760 points

Model AM3358BZCZI00, programming software WINCE 7.0

0 Biser Gatchev-XID over 8 years ago

TI__Guru**** 393215 points

Pin V9 can be assigned as:
GPMC_CSN2/GPMC_BE1N/MMC1_CMD/PR1_EDIO_DATA_IN7/PR1_EDIO_DATA_OUT7/PR1_PRU1_PRU_R30_13/PR1_PRU1_PRU_R31_13/GPIO1_31
Pin C12 can be assigned as:
MCASP0_AHCLKR/EHRPWM0_SYNCI_O/MCASP0_AXR2/SPI1_CS0/ECAP2_IN_PWM2_OUT/PR1_PRU0_PRU_R30_3/PR1_PRU0_PRU_R31_3/GPIO3_17

In the AM335x Starter Kit pin C12 is used in ECAP2_IN_PWM2_OUT mode as PWM output to the LCD backlight. I cannot say how these pins are used in WinCE, because this software is not supported by TI.

0 Meng jeffrey over 8 years ago in reply to Biser Gatchev-XID

Expert 2760 points

I used to control the back light out just make pin output high and low level, do not need to output PWM waveform, I want to know is whether the V9 pin can be set low 1 s at system initialization, and then has been high.

0 Biser Gatchev-XID over 8 years ago in reply to Meng jeffrey

TI__Guru**** 393215 points

Pin V9 is high-impedance with an active pulldown resistor during reset and at reset release time, so it should be low by default. What you should check is your SYSBOOT sequence. If any GPMC device is included in the boot sequence, ROM code will change the default state of this pin.

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AM335X: Pin usage questions