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Support Forum » Mistook MCU Pin 25 for Row 25 for Step 7a: Did I zap the MCU?

December 30, 2010
by jnewsom
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Last night I got my NerdKit up and running and got the desired output on the LCD telling me what I was good to go.

During step 7a I mistook "... take a wire and connect row 25 on the left side" for MCU pin 25 (on the right side, that'll teach me reading comprehension) and connected MCU pin 25 (PC2/ADC2) to the GND rail.

I can't get the success message anymore and can't see any output to the LCD display. I went ahead and backed up my work to the baseline for Step 6 and have verified my connections.

I see roughly 10v from the 9v battery and see 5.4v on the + rail so I know the voltage regular is working correctly. I verified that my 1K ohm resistor is good to go (I see 2.56v across the resistor).

The only thing I can think of (besides n00b mistake of loose connection, which I think I've gone over the connections multiple times) is that I zapped the MCU. Is that a possibility with connecting MCU pin 5 to the GND rail?

December 30, 2010
by jnewsom
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Correction: Last sentence that should be "... connecting MCU pin 25 to the GND rail?" and not pin 5.

December 30, 2010
by jnewsom
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I don't think I zapped the MCU. I went on with Step 7 and connected the USB cabling to the breadboard and was able to program the MCU with the initialload code via make.

I must have a loose connection to the LCD some place.

make output:

8<-----------------------

avr-gcc -g -Os -Wall -mmcu=atmega168 -Wl,-u,vfprintf -lprintf_flt -Wl,-u,vfscanf -lscanf_flt -lm -o initialload.o initialload.c ../libnerdkits/delay.o ../libnerdkits/lcd.o ../libnerdkits/uart.o avr-objcopy -j .text -O ihex initialload.o initialload.hex avrdude -c avr109 -p m168 -b 115200 -P /dev/ttyUSB0 -U flash:w:initialload.hex:a

Connecting to programmer: . Found programmer: Id = "FDL v02"; type = S Software Version = 0.2; No Hardware Version given. Programmer supports auto addr increment. Programmer supports buffered memory access with buffersize=128 bytes.

Programmer supports the following devices: Device code: 0x35

avrdude: AVR device initialized and ready to accept instructions

Reading | ################################################## | 100% 0.00s

avrdude: Device signature = 0x1e9406 avrdude: NOTE: FLASH memory has been specified, an erase cycle will be performed To disable this feature, specify the -D option. avrdude: erasing chip avrdude: reading input file "initialload.hex" avrdude: input file initialload.hex auto detected as Intel Hex avrdude: writing flash (7794 bytes):

Writing | ################################################## | 100% 1.22s

avrdude: 7794 bytes of flash written avrdude: verifying flash memory against initialload.hex: avrdude: load data flash data from input file initialload.hex: avrdude: input file initialload.hex auto detected as Intel Hex avrdude: input file initialload.hex contains 7794 bytes avrdude: reading on-chip flash data:

Reading | ################################################## | 100% 0.97s

avrdude: verifying ... avrdude: 7794 bytes of flash verified

avrdude done. Thank you.

----------------------->8

December 30, 2010
by jnewsom
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And the conclusion to this thread:

After taking a break I pulled off all the LCD wiring off the bread board and re-wired it all again. Plugged in the 9v battery and... Huzzah! The initiaload code was displayed to me.

Glad to see that I didn't blow away the MCU earlier.

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