In-Circuit Programming of the MCP25050 CAN I/O expander

kender · Joined: 09 Aug 2004 Posts: 768 Location: Silicon Valley

Colleagues,

At a glance, MCP25050 I/O expander looks like a device, which doesn't require firmware ? just a bunch of registers. However, the datasheet says that they are in-circuit programmable. Do they have to be programmed?

Thanks,
Nick

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

The User's Guide says this:
"The user memory for MCP250XX devices is initially blank when shipped
from the factory. The user must program the user memory with user-
defined defaults."

Also, the data sheet shows the default state of the registers.
Most of them power-up in an indeterminate state.

http://www.microchip.com/stellent/idcplgidcplg?IdcService=SS_GET_PAGE&nodeId=1335&dDocName=en010402

ratgod · Joined: 27 Jan 2006 Posts: 69 Location: Manchester, England

Does anyone know if CCS has released any more info regarding programming the MCP250xx devices with the ICD-U units?

I read somewhere about using transistors to drive programming from separate power source.

ratgod · Joined: 27 Jan 2006 Posts: 69 Location: Manchester, England

I found the answer to my own question,
the CCS FAQ has the required details

http://www.ccsinfo.com/faq.php?page=mcp250xx

I hope this helps others