topic Programming MCF52233 via the EZPort in ColdFire/68K Microcontrollers and Processors

Programming MCF52233 via the EZPort

expo — Thu, 08 Feb 2007 05:54:25 GMT

Hello everyone,

I had a question regarding programming the MCF52233 via the EZport. More specifically, about the RCON/EZPCS pin. Our target board has that pin tied high through a 4.7K resistor. After reading through Chapter 21 of the MCF52233 Reference Manual I was confused about how that pin needs to be treated. Here is what I gather:

- The RCON/EZPCS pin should be low when coming out of reset so that you enter the programming mode.
- Once in the programming mode, the next time this pin goes low it will signal the first SPI transfer.

If this is true, that means that whatever I use to program the device via the EZport will need to make sure that the RCON/EZPCS pin is low when the target board is powered up.

Does this all sound correct? Or am I missing something?

Thanks in advance,

Reuven

Re: Programming MCF52233 via the EZPort

lambtron — Wed, 09 Jan 2008 01:31:23 GMT

Based on my reading of the documentation your analysis is correct.

I have another question about the RCON/EZPCS pin: does it have an internal pull-up or is an external pull-up required? The Pin Functions table says "pull-up" in the Pull-up/Pull-down column. Since external logic could potentially have either a pull-up or pull-down here, I assume the table is stating that there is an internal pull-up, but there are no notes to support this assumption. Is this correct?

Similarly, the TEST pin shows "pull-down," but other documentation says that this pin must be connected to Vss. I'm confused! Is there an internal pull-down on the TEST pin, or is the table saying that it must be externally pulled down?