This message contains an entire topic ported from a separate forum. The original message and all replies are in this single message. We have seeded this new forum with selected information that we expect will be of value to you as you search for answers to your questions.
I have a question regarding running the Bootloader from RAM, we currently use the serial Bootloader from the freescale site, this copies itself into RAM and moves RAM to the upper 4k of flash to overlay the Bootloader allowing all other flash locations to be programmed. I cannot see in either of the CAN Bootloaders RAM being moved to the upper 4k of flash.
Date: Wed Feb 16, 2005 2:13am
Date: Wed Feb 16, 2005 2:53am
Yes I understand this, the problem I have is that the serial Bootloader I use at the minute writes to the INITRM register to move the RAM to the top 16k address location, so the rest of the flash can be programmed except the Bootloader. The two CAN Bootloaders I am using as reference get copied into RAM via a LRAE but do not appear to write to this register thus leaving the RAM in its default location, I am trying to ascertain if there is a reason for the RAM being left in its default location.
The main reason to move the RAM to the top of the memory, is if you want to process interrupts while executing the Flash programming algorithms from the internal RAM (since the high Flash page is available to supply the interrupt vector when this Flash block is being updated).
Message Edited by Dietrich on 01-29-2006 11:36 AM
Message Edited by Alban on 01-30-2006 10:33 AM