Hello all, I’ve been struggling to get my ATSAM7S256 (on an Olimex SAM7-H256 Board) to blink, or do anythign for that matter.
For the past (I don’t even know how many) months, I’ve been trying off and on to get started on it, using many different blink led tutorials.
Many of those were the eclipse/yagataro tools.
I found Crossstudio, and have actually connected to my arm. (I’m using an Olimex ARM-USB-OCD JTAG adapter)
Now my problem is that when I try and do anything with my target, I get an error
Cannot halt target after reset
I have done some researching, tried to change the setting on my JTAG connection, and even went the "Generic RS232 port" in Crossworks. I've tried the powerdown,test jumper+power up+10,power down, and nothing.
AT91SAM7 parts have a reset pin, NRST. Unfortunately, the micro can set the RSTC_MR control register to ignore NRST - and “ignore” is the default setting. What were they thinking?
Would this have anything to do with my inability to stop the cpu after a reset? Or is it clearly resetting?
If you look at the schematic of the olimex development board, you will see it has an reset supervisor. This can of course only work if the #RST pin is an input.
And that is also exactly the case. If you want to use it as an output, you have to activate it manually with your code by configuring the reset controller inside the SAM7S256. The SAM7S256 does not ignore the #RST pin by default. only if you tell it to.
You might want to take the easy road and use the embedded bootloader of the SAM7S256. Just create a bin file and load it with SAMBA in the processor. If that works, you can start to figure out why your Jtag device does not seem to operate with your MCU.
You might want to try my arm ide distribution. It is based on Yagharto but i have made a project manager that keeps track of a lot of things.
It is not perfect and is still beta but it works and will allow you to do at least some developing. It does not work with jtag at the moment but i am sort of actively looking around how to implement at least some basic jtag functionality (scanning registers) for the future. It works with SAMBA.
W-ARM is free and can be downloaded from sourceforge.
In the near future i want to release an update that will have a lot of bug fixes and more functionality.
When it is that time, i will post on relevant forums that i have a new version. But it may take a couple of months.
I have also made several pdf files explaining functionality.