8-bit Microcontrollers中的主题 Re: Monitor Mode 68HC908QY2

Monitor Mode 68HC908QY2

BillB — Sat, 19 Aug 2006 00:47:05 GMT

Description: I am trying to establish communication with the new low pin count part, trying to get it operating in monitor mode so that I can program it. I am using the same hardware and software that I have been using for the 68HC908SR12 part which we have been using for years. I have not had any success. Conditions: I am providing a 9.8304MHz clock into osc1 pin 4, 5V to VDD pin 1, VEE pin 16 to gnd, PTA1 pin 12 to 5V thru 10K, PTA4 pin 5 to gnd thru 10K, PTA0 pin 13 is digital I/O, connected /IRQ pin 9 to the higher voltage required for monitor mode, RST pin 8 to 5V thru 10K and am using "PROG08SZ.exe" software. Please review and let me know if you see a problem. I have gone over my connections verifying against the data book several times and am about out of tricks. Thanks so much for any help.

Bill

Re: Monitor Mode 68HC908QY2

peg — Sat, 19 Aug 2006 06:16:37 GMT

Hi Bill,

Your connections appear correct so what is the software telling you is going wrong?

Regards David

Re: Monitor Mode 68HC908QY2

lucyperek — Sat, 02 Sep 2006 07:00:12 GMT

There is one strange bug there. You must connect circa 10 nF between IRQ and ground. Whithout this cap I always observ some strange oscillations there. And of course remember that VDD must go below 0,1 V during POR. So make a switch which not only removes power but also connects VDD during POR to ground. It must work.

Re: Monitor Mode 68HC908QY2

peg — Sat, 02 Sep 2006 08:27:06 GMT

Hi Lucyperek,

I have never encountered any problem with the IRQ pin as you describe. No caps on it!

Also I have only 0.1uF on the MCU side of the power switch so it discharges quite quickly.

Of course doing as you say should still work.

Regards David