µTasker Forum
µTasker Forum => NXPTM M522XX, KINETIS and i.MX RT => Topic started by: neil on September 16, 2009, 11:37:01 AM
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Hi Mark,
I have a board where I use a port extender chip from Maxim, and one of the outputs control the *reset pin of the Atmel SPI Flash. This works fine, but I forgot that the bootloader wont work, as the IIC is not used, therefore the extender cant be programmed to bring the device out of reset. If I connect the reset pin directly to 3.3v, do you see a problem? This means I can reset the chip, but wonder if there is ever a need to do so.
As its just a prototype board, I have 1 pin left , so I can connect it to pin AN2 (pin 68) of the 52259 (144 pin version), and wondering how the bootloader would handle this?
Neil
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Hi Neil
The reset pin on the ATMEL SPI chips may be useful for resetting the SPI FLASH state-event machine in case there were a reset of the processor during programming or similar. Generally it is connected to the RESET line of the processor so that that operates automatically - can you do that?
Regards
Mark
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Hi Mark,
Is it better to place it on the *RSTOUT or *RSTIN pin? I have the PHY connected to the *RSTOUT, so would it make more sense to have it to this pin, as I can reset it at any time.
Neil
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Hi Neil
You may have problems connecting it to the RST out in your system due to the fact that the line is being used to control the PHY. It is probable that the SPI FLASH is already being accessed before so 'may' cause conflicts.
The RST in line will probably not be controlled appropriately so it may be best to use a spare GPIO (of possible) which defaults to the reset state and can be put to the '1' state by code before being used.
Regards
Mark
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Hi Mark,
If I place it on AN2 pin, I suppose I would have to make sure that the bootloader code sets this in high too? Where in the bootloader is the best place to put this code?
Regards
Neil