3 Aug 2005 marcin   » (Journeyer)

Haven't done much robot stuff this week, as I have family visting from overseas.

By not using a basic stamp, PIC or AVR, (I'm using a Renesas M16C) I realise that I'm actually making more work for myself as there isn't such a body of knowledge that can simply be plagarised from. For example, I'm trying to do this SRF04 interface for the M16C based on a single timer and a 5-state FSM. Basically, it should go:


state:      next state:      transition:      
INIT        READY            10ms timer IRQ
READY       TRIGGER          srf_trigger() function call
TRIGGER     TX               10us timer IRQ
TX          MEASURE          pulsewidth measure on falling 
                             edge on input or timer over/
                             underflow
MEASURE     READY            10ms timer IRQ

This is based on the expected behaviour shown at the srf04 main page. I'm finding it a bit difficult to get the thing to behave as expected.

Don't get me wrong though, I'm using the M16C starter kit plus (SKP) (it costs about $50 from memory and comes with a C compiler) and I really like it. The SKP board is fairly small (measures about 10x6 cm), has a 2x16 LCD, 3 buttons, 3 leds, and heaps of I/O (you attach the headers), and comes with a USB based programmer/debugger. The uC has 11 timers, 2 or 3 uarts, 3 or 4 INT pins, heaps of ADC. So it does have quite a bit going for it (not to mention about 16 or 32K RAM and a couple of hundred K flash. You can see the one I'm using here.

Cheers, Marcin. (marcincoles__at__yahoo.com)

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