[sdiy] Using Cortex Mx Arms in Synth DIY

[ryan williams]

I have used the LPC2478, LPC2388, and LPC1768 (cortex m3) at work.
Previously I used AVRs on for fun projects but now prefer the LPC
devices. The peripherals are easy to setup and these devices have good
performance. I dont have any experience with the cortex m0 yet.

I have briefly played with GCC and eclipse. It seems to be somewhat
easy to use. At work I have Keil tools and those are nice but much to
expensive for DIY use. I'm actually working on a synth project using
the LPC1768 and plan to use LPCXpresso for it. That development system
is very easy so far. Once registered it has 128k limit, not 64. Those
LPCXpresso boards are super cheap and traces can be cut and then it
can be used as a debug interface for your own boards. I was hoping to
use the NXP cortex M0 for this project, but I needed more I/O pins
that the LPC1700 devices provide.

On Sat, Dec 24, 2011 at 1:59 AM, Paul Maddox <yo at vacoloco.net> wrote:
>
> 5. Have slow IO.
>
> last I looked you couldn't access the IO on some of the devices as fast as the chip could run, for example the philips LPC series, I can't recall where I saw it but the IO would only run around 12Mhz, I real shame if you want to use some 20Mhz SPI.
> I've been looking at the XMEGA range, which is a step up but I wonder if I'm just delaying the inevitable.
>

Paul, the problem with slow GPIO was more of an issue with the earlier
LPC devices. The newer ones have a Fast GPIO mode which is better. In
both cases, GPIO is done with a peripheral which has its own clock
divider. you can set that to 1. I was just reading on the NXP forum
about some tests done where they got 25MHz pulse wave on a 100MHz
clock (cortex m3). Thats an assembly loop. I havent been able to find
much information in the data sheets.
Also this does not apply to other peripherals. According to NXP's
LPC1700 presentation, the LPC1700s can can do up to 40Mbit/s SPI
transfers using the SSP interface. I'm not sure about the M0.

-Ryan