[SOLVED] How can ATMEGA auto detection?

[nagendra.singh]

I have a 32pin possibly atmel controller.After matching with datasheet i found it is ATMEGA48 OR ATMEGA88.

Is there any way with any programmer to know exact number of mcu.

 

[alexan_e]

Every mcu has a signature

 

[nagendra.singh]

sir,

can we read locked mcu signature?

i was able to read only new blank mcu signature.

 

[alexan_e]

I don't think that the lock is related to the signature reading, it just prevents reading/writing the eeprom /flash until you erase the chip and since an erase is possible you should be able to read the signature.
Maybe the ISP is disabled in your mcu so you can't communicate with it unless you use a parallel programmer.

Alex

 

[nagendra.singh]

Which programmer and software to communicate?

can i make lpt programmer?

 

[alexan_e]

One solution is to make a parallel programmer or use the fuse bit doctor **broken link removed**

 

[nagendra.singh]

i buy a usb programmer clone that is working with avr studio 4.0 in stk500 mode.

i connect atmega8 28pin dip package successfully read signature.

but now i try to connect atmega88v 32pin smd tqfp package but no success. i connect pin as

pin4- gnd
pin6- +5v
pin15 -- mosi
pin16-- miso
pin 17--sck
pin29-- reset

but i an not able to read signature.pls help me.should i need any modification as external crystal or any other ?

this is new unused chip.

 

[alexan_e]

Your power supply connection is not correct,
3 and 5 are GND
4 and 6 are VCC

 

[nagendra.singh]

sorry it was connect in that way i write wrong as pin3

should i need to connect both pin 3 & 5 to gnd and pin 4&6 to 5volt?

i only connect pin3 to gnd and pin6 to +5volt.could it be th reason.

 

[alexan_e]

I would suggest you connect all four supply pins and retry, normally all power supply pins have to be connected

 

[nagendra.singh]

nothing happening. i also try with atmega8 smd version.

28pin dip packege atmega8 and 48 connected pretty well.

any other solution ?

 

[alexan_e]

How do you make the connection?
Are the chips mounted in a board, on a base ?

Are you sure there are no short circuits?

 

[nagendra.singh]

first i try with direct wire

then on the board.but no success.

 

[alexan_e]

I think it is a connection problem, it is not so easy to connect an SMS component on the fly.
When you say on the board what kind of board do you mean?
Does it have a programming header on it?
Have you soldered SMD components before, are you sure you have done it properly?

 

[nagendra.singh]

all four programming pins track are open and 5 volt and gnd connected near to mcu supply line

i will arrange tomorrow dip version mcu then i will try.

 

[nagendra.singh]

successfully connect with atmega88pa 28 pin.

but with atmega88v smd tqfp 32 pin no connection with programmer.

i have no problem with any smd repair up to BGA. changing.

 

[nagendra.singh]

what is cal byte[read only] in atmega ? i read many new non programmed atmega ic with XELTEK super pro 500p programmer but this value always different like 99, B0, A8.

 

[alexan_e]

The calibration byte depends on the device in order to tune the internal RC to better accuracy.

 

[nagendra.singh]

i program some mcu but which cal byte is 99 working well.but with on empty chip read found other value like 93 a4 is not working well.output frequency is high.

do we have to write cal value same or different for each ic.it is working well which have cal value 99.

 

[alexan_e]

Are you referring to ATmega88?

In this device the internal RC is working at 8MHz (no other alternative frequencies) so there is only one calibration values and it is automatically copied to OSCCAL so you don't need to do anything.

• Bits 7..0 – CAL7..0: Oscillator calibration value
The oscillator calibration register is used to trim the calibrated internal RC oscillator to remove
process variations from the oscillator frequency. A pre-programmed calibration value is automat-
ically written to this register during chip reset, giving the factory calibrated frequency as specified

Alex