topic MCF5274L Reset Problem in ColdFire/68K Microcontrollers and Processors

MCF5274L Reset Problem

Southernboy — Wed, 20 Aug 2008 01:38:52 GMT

I have a particular problem with the processor reseting. After applying power to the cpu, the RSTOUT signal is low, and even giving the CPU a reset will not get the cpu working. The RSTOUT signal stays low for the duration of the reset.

I have tried keeping the RSTIN signal low, and taking the RSTIN low and then back high, but the RSTOUT signal remains low. Also I have kept the RSTIN signal high during powerup, with still no affect.

The problem does not occur every time, but some processors/hardware seems worse than others. Some boards are fine, others are quite bad (ie 1 successful reset in 5).

When the problem occurs, it seems the processor is locked up, and cannot be recovered, apart from repowering the device.

Has anyone any experience of this?

Thanks in advance

Neil

Re: MCF5274L Reset Problem

taigbr — Wed, 20 Aug 2008 14:34:54 GMT

Hi Neil,

are you sure your clock is runnung?
Are you using RCON? The values are read while RSTOUT is active.
You might want to take a look at the RSR register to find out the
reason for your reset.

Georg

Re: MCF5274L Reset Problem

Southernboy — Wed, 20 Aug 2008 14:49:43 GMT

Hi Georg,

Thanks for the post. RCON not used and is pulled high using a 4K7. The clock is from a 25Mhz oscillator, not a crystal. I am using the CLKMOD settings of CLKMOD[1:0] of 1:0. (normal mode with external reference).

Thanks.