8-bit MicrocontrollersのトピックRe: Wire GR8 For Real World Use?

Wire GR8 For Real World Use?

AveryZ — Thu, 12 Oct 2006 07:56:42 GMT

Hi,

I have a GR8 that I built a programmer for, loaded with code, and now I am ready to move it into its actual real home. I am having trouble figuring out how to wire it so that when it recieves voltage/turns on, it just jumps right into the program code thats on it.

Forgetting about where I/O is wired, I connected Vdd and Vss, Vdda and Vssa, and Vdda/ref and Vssa/ref to ground and voltage respectively. I have also connected OSC1 to my crystal which is 9.8304. Is there anythign else that should be wired?

Also I am communicating with the PC over SCI, and I have the two wires plugged directly into their respective ports on the chip, should they be going through a MAX232?

Thanks Guys!
-Avery

Re: Wire GR8 For Real World Use?

bigmac — Thu, 12 Oct 2006 10:04:02 GMT

Hello Avery,

Avery Z wrote:

... I connected Vdd and Vss, Vdda and Vssa, and Vdda/ref and Vssa/ref to ground and voltage respectively. I have also connected OSC1 to my crystal which is 9.8304. Is there anythign else that should be wired?

Did you provide separate de-coupling capacitors at each of the supply connection points, as specified in the data sheet? Did you connect the crystal as a Pierce oscillator configuration, as shown in Fig. 28 of the data sheet? This involves connections to both OSC1 and OSC2. For a 9.8304 MHz crystal, the resistor Rs can usually be omitted, and make C2 a fixed capacitor of the same value as C1. What component values do you currently use.

Avery Z wrote:

Also I am communicating with the PC over SCI, and I have the two wires plugged directly into their respective ports on the chip, should they be going through a MAX232?

Very definitely. You may have already damaged the chip!

Regards,

Mac

Re: Wire GR8 For Real World Use?

AveryZ — Thu, 12 Oct 2006 12:57:18 GMT

Mac,

Thanks so much for your speedy response! I will implement these changes immedietly! I don't think the chip is damaged from the SCI already, b/c I can put it back into monitor mode and it works fine, but we'll see!

Thank You!
-Avery