This discussion has been locked.

You can no longer post new replies to this discussion. If you have a question you can start a new discussion

ARM newbie...newbie questions!

Note: This was originally posted on 8th February 2012 at http://forums.arm.com

Hello everybody,

this is my first post in the forum. I'm an AVR 8-bit user curious about the ARM world, the Cortex M0 side in particular.

I would like to make a two-processor system, where the video and audio part is generated in software on a little NXP LPC11xx device. The video signal should be a framebuffered 320x200 VGA.

For this to work on a LPC11xx, I need to know a few tech details, and I felt that asking for them here was the thing to do before investing time in the platform.

So, here they are:

Does the M0 allow you to connect an external SRAM chip and map it inside the address space, as if it where internal RAM? Does accessing it have cycle penalties? For example, AVRMEGA128s can do this up to 64KB, with 1 cycle penalty per read/write instruction, leading to 3-cycles reads and 3-cycles writes.
I still have to understand how to drive pins...it looks like you have to write to particular memory addresses, right? How many pins can I set with a single instruction, and how many cycles does it cost?
Ideally the chip should be clocked at 50.35 Mhz, to respect VGA timings. Is it possible to set it to this clock freq?

Thank you very much for any answer.

Top replies

Alban Rampon over 12 years ago +1

Note: This was originally posted on 10th February 2012 at http://forums.arm.com Hi and welcome nevez, As you probably know, ARM only deals with the core of the microcontroller. Therefore even if the architecture...

Stephen Cantini over 12 years ago

Note: This was originally posted on 10th February 2012 at http://forums.arm.com

Thank you very much for the links...I'm still learning how to move and where to look, in the ARM community!

I'll ask for info in that forum.

Cheers
Cancel
Vote up 0 Vote down

Cancel
Alban Rampon over 12 years ago

Note: This was originally posted on 10th February 2012 at http://forums.arm.com

Hi and welcome nevez,
As you probably know, ARM only deals with the core of the microcontroller. Therefore even if the architecture can allow such or such feature, it is more with the silicon implementation that you need to see if it was done or not...
For instance, the default memory map of the Cortex-M0 is as follow: http://infocenter.ar...m/CHDHCADA.html but weather adding SRAM is directly on the bus or would have to be done through SPI (for instance) depends on the micro itself. (for more info on the architecture, please have a look at the ARMv6-M Architecture Reference Manual)
For NXP, I can recommend the NXP LPCZone for its trainings videos and code or NXP MCU Discussion Forum for a more personalised approach
HTH,
Alban
Cancel
Vote up +1 Vote down

Cancel

ARM newbie...newbie questions&#33;

Top replies

ARM newbie...newbie questions!