AVR HVSP Fuse Resetter

description

in working w/ 8 or 14 pin avr devices, i would sometimes want to use the RESET pin as io as the io pin count is low. but doing so will disable further programming via SPI. i do not need a full blown HV programmer, just a way to revert these devices to factory default fuse settings so that i can use SPI to flash them again. it is also handy as sometimes by mistake i may burn wrong fuse value and brick my devices.

this project is created so that if i could revert the RESET fuse change and flash via SPI again. it employs the high-voltage serial programming (hvsp) available for such devices. note that this is not to be confused w/ the high-voltage parallel programming used for 20pin+ devices (i.e. tiny2313, mega8, etc).


features

* reads device signature and hi-low fuses for hi-voltage serial programmable attinys
* reset hi-low fuses to factory default on target devices
* layout to drop-on attiny13, attiny25/45/85 8 pin devices targets
* attiny24/44/84 targets needs additional breadboard and jumper wires
* standalone operations, fuses values show on 7 segment display
* cannot reset fuse for attiny2313 and atmega devices as they requires hi-voltage parallel programming

Example Operation

Step 1 Design Notes

design notes

to minimise project component count, the 4 digit led module is directly driven by the 2313's io pins. neither transistors nor current limiting resistors are used. for more detail implementation notes, please see my digital alarm clock project. the led driving takes up 12 io pins (4 digits + 7 segments + decimal point).

for hvsp purpose, we need to have 6 io pins from t 2313. we need to supply 5V Vcc, 12V to RESET, SCI (serial clock input), SII (serial instruction input), SDI (serial data input) and SDO (serial data out). for that we employ the rest of the free io pins from the 2313, plus some io pins are shared between led driving and hvsp control.

one single tactile button is used to accept input, this io pin is shared between button input and led driving.

upon attaching power firmware reads target mcu device signature via AVR's HVSP (High-Voltage Serial Programming) interface. it then look up the device name by matching the device signature. in turn, fuse values (hi, low and extended) are read from device.

fuse values can then be read by pressing the tactile button, which cycles thru device name and various fuse values in hexidecimal format.

pressing and holding the tactile button for about one second will instruct firmware to write the factory default fuse value to the target mcu device. after writing, firmware re-reads the new fuse values for display.

at all times a timer interrupt is used to perform led multiplexing. brightness can only be adjusted by source code change.

i had included the more common device types, source code is provided so that different / additional device can be added to the firmware. please note that only devices with HVSP support can be used.

the circuit requires a main power of 12V supply, a 78L05 voltage regulator brings a 5V Vcc for the 2313 to operate. a 2n2222 is used to switch on 12V towards the target device's RESET pin when HVSP read / writes are being commenced.

Comments

[Wally Ao]

Whether the 7 segment led display is common cathode type? The schematic shows
the pin 5 of the 2313 connect to the pin 3 (DP) of the display. Whether it should be connected to the pin 2 (segment D)?

[simpleavr]

the led is of common cathode type, pinout is the same as the one in this project
http://www.simpleavr.com/msp430-projects/3p4w-clock
looking at the schematic, i understand it is wrong. both the breadboard and the schematic are generated by a very early version of fritzing.
I start out by using the breadboard layout 1st. and it appears to be more correct.
pin 4 (not 5) is actually connected to pin2 of led. since the led module is layout directly on top of the 2313, all pins should be aligned like so
i.e.
2313 pin 3,4,5,6,7,8 tied to led pin 1,2,3,4,5,6.. and
2313 pin 13,14,15,16,17,18 to led pin 7,8,9,10,11,12

the schematic here is a little bit bigger, but still wrong.
http://www.simpleavr.com/avr/hvsp-fuse-resetter

please also compare the pictures and breadboard layout if needed.
guess u are the 1st trying to build this, thinks for your input.

[Wally Ao]

Dear SimpleAVR,

I have no luck that my fuse resetter didn't work. I have checked many times and would not find out what was wrong. I would like to ask for your help to double check my schematic. The hex file and the eepom file were built by AVRstudio 4 using youe c file without any modification. Thanks in advance.

[simpleavr]

i haven't touched avr's for > 1yr. now playing w/ msp430.
can't really read out your schematic as it's small.
from the pcb layout everything looks good.
w/ no target mcu attached, the system should show "0000" upon power up. if otherwise. i would check
. 2313 fuse, make sure chip is not locked. is set internal osc, 8mhz, etc.
. use multi-meter, check power to 2313.
. u also rely on the push-button to pass Gnd, check if that's good.
. use diode test setting on your led module, make sure the pin-out is what we want (also cathode / anode), they should light up fadely upon probing.

if that doesn't work, please PM me w/ detail diagnosis results. I will find my project (must be somewhere in my drawers) and trace from there.

* it's also good to try burn a simple led blinker firmware on your 2313 to make sure chip is good and fuse is ok.

[Wally Ao]

Hi SimpleAVR,

I could not find the PM link in instructables nor simpleavr.com. I would like to contact you here.
. LED module did not light up upon power up.
. HEX code write to MCU is OK. 8MHz and set L fuse 0XE4, H fuse 0XDF, E fuse 0XFF.
. Pin 20 Vcc voltage is 5.05V.
. Push switch checked OK.
. Apply V- to led module pin 12, 9, 8, 6 and V+ to other pins. The module light up normally.
. The voltage of the transistor at B 0.76V at C 0.05V. It should be saturated.

[simpleavr]

@Wally,
text getting big, i started my response at top, please see.

[Wally Ao]

Many thanks Simpleavr. The hardware problem has been solved. As soon as I swapped the Led module to a common anode type, the resetter was operating.
It reset the Attiny 85 to defaule setting 0x62, 0xDF, 0xFF. But it can not reset
Attiny 25. It read t25, 437d, FF00. I am an AVR programing dummy. Would you please help me to include the resetting of Attiny 25.

[simpleavr]

i never had a tiny25 to really try it (tiny45/85 all cost the almost the same). but all 25/45/85 have the same spec and i use the same datasheet to workout the timing, instructions etc. so it should work the same.
i think u should 1st try 25 and 85 alternatively a few times and ensure that the problem in the 25 is consistent (may be even try a few 25s if u have more than one).
if result is not consistent (i.e. 25/45/85 all can mess-up), u should try and look at your HV voltage from the transistor switch (I used a 3904, 2222 should work, not really know if the switch time can / will make a difference)
i also had not tried many varieties, i.e. i tried 13, 13v, 44, 45, 85 only. if u had 25a, 25v i don't know they are the same.
u could also try to increase the timing when clocking HVSP instructions.
u can do so by altering the _delay_ms() commands, may be add 10% more to them. it appears that u are reading something for the tiny25 but they are out of sync.
good luck and happy hacking.

[Wally Ao]

Dear simpleavr,

The tiny that I have resetted is Attiny25V-10SU. I found that it was successfully resetted. The problem was I have written the ISP frequeency of the programmer too high at 125KHz. When I reset the ISP at 64.8KHz, the chip can be written as usual. Now, I have tested 13A, 25V, 85V are being resetted successfully.
Thank you very much for your help.

[simpleavr]

@Wally Ao,

I took out my original build and compare your test results.
. transistor voltage is right.
. correction, the start-up display should be "t00" if not target present.
. same result probing the led module. (multimeter diode test, pin 12,9,8,6 w/ RED probe, BLACK probe on others, segment light up.
. fuse correct.

suggestions
. i used avrgcc to build, if under windows, try turn off any optimization flags, compiler may "play smart" and optimize some code away.
. if not sure about the cathode / anode, try comment in/out
#define _REVERSE
and see
. may want to comment out the "read_chip()" inside main() and instead do
seg2port(0x12, 0x40); seg2port(0x34, 0x42);
this will force loading and displaying "1234" on led module.
. if physically possible, remove transistor and leave circuit to just led module and try.
. may be write a simple firmware that just blinks a led segment (pin12 + pin11, reversing output every second). just to verify your build and burn procedure.

[computurwizard]

Can you use an Atmega8 in place of the 2313? Just wondering as I do not have any 2313's on hand :/

Excellent Instructable BTW, thanks for sharing!

[simpleavr]

u will need to change some register and may be relocate the pins according to your schematic / layout. i recall the timer registers is different between the mega device and the tiny devices.
u could try and alter the makefile and change MCU=attiny2313 to MCU=atmega8 and try. fix any error the compiler has for u.
i haven't touch my avr's for many months now. i am spending time w/ ti's msp430 / launchpad.

[NickYa]

Can it reset Atmega8 or any other Mega?

[simpleavr]

@nickya sorry, this one can only do "serial" high-voltage protocol. atmega8 requires a "parallel" HV protocol. this reader / resetter can only do 8 pin or 14 pin AVR attiny devices.