Issue about GPIO

[tony_l_cai]

Hi，all

    1. on the MX6SL, I cant understand some Pad characteristics ,so when I set the pad characteristics, I dont know how to set them. such as  SRE (1 bit slew rate control),which case is the Fast and Low slew rate applied to?

     HYS (1 bit hysteresis control), the difference between CMOS and Schmitt trigger？

     DDR_MODE_SEL (1 bit ddr_mode control),DDR_INPUT (1 bit ddr_input control)， how to use in DDR interface in detail?

     2. SION bit, maybe the illustration in mx6SL reference manual is so  abstracted. I can't understand how to use it,please give me an example, 3Q

     3. we can see the mx6DL has no LVE to set the GPIO voltage on signal "1", and we must use change its voltage domain. So in MX6SL/MX280,could we have some voltage domain to change the GPIO voltage?

     4. Last time , I know how to select the input path on the MX6SL by Daisy chain. And it is just one route that a mux signal input from one pad, could I select the same mux signal from different pads at the same time by the daisy chain?

[igorpadykov]

Hi tony

1. for HYS bit meaning suggest to look at

Hysteresis - Wikipedia, the free encyclopedia

for DDR_MODE_SEL ,DDR_INPUT explanation is given below

IOMUX/DCD DRAM configuration confusion...

2. SION bit is used for reading pad value directly by GPIO, regardless of iomux settings

3. i.MX6SL has GPIO dual voltage selection using LVE (GPIO supplies NVCC18_IO, NVCC33_IO)

IMX6SLHDG  sect.7.2.4 Power-up sequence in low voltage system design gives some details

4. from different pads selection at the same time is not possible

Best regards

igor

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