Re: [Amforth-devel] Progress and More Difficulties with Hello World exercise

[D N. <dny...@at...>]

On 3/27/2011 8:22:27 PM, ken...@al... wrote:
 > Hi, I soldered in a crystal and a couple of caps and
 > it's working fine
 > now, Amforth seems much more sensitive to clock frequency than the
 > Arduino C programs.
 >
 > I've
 > had no trouble with the serial interface running C programs on the
 > BBB. That sent me on some wild goose chases trying to figure out what
 > was wrong with Amforth.
 >

As I understand it, the amforth way of dealing with interrupts on the 
serial port is to have the ISR set a flag, and the uart is truly 
serviced when the inner interpreter steps to the next word. There is an 
elegance to that approach, as it allows secondary ISR to be written in 
forth, but it has more latency than a traditional ISR (grab byte and 
stuff into ring buffer immediately). Without hardware drtiven serial 
handshake, that increased latency may account for the greater  
sensitivity to timing?