Software serial Rx issue with ATMEGA644

Hi,i'm uses amega644P whith arduino and Myght core(from guithub) as a bootloader.The problem is when i uses Software serial library, Rx does'nt work. I try the second serial port on ATMEGA644 and my communication is perfect. I need 3 serial port, so in addition to serial and serial1 i need to define a third serial port with software serial library. Thanks for helping me.

Please link to the core you are using

Thank you for your replay,
this is the core

What's your real chip name? The ATmega644 (non p) only have one serial port, so it can't be that one.
What version of the core are you using? Install the latest one :wink:
Are you getting any error messages when compiling, or is it just not working?

The problem could be in your pin configuration, pin numbering or interrupt numbering mismatch.
Provide more detailed info.

My chip is Atmega644 AU in datasheet it have 2 serial ports .
the core version installed is the latest.
I uploaded the bootloader of atmega644 because there is 2 choice 644/644A or 644P/644PA, if i try to use bootloader of 644P arduino error is unknowing mcu.
When programming, if use serial programming "Prolfic" i choose 644P (bootloader is 644A), if i choose 644A (idem with bootloader) i have error in compiling, but when i choose 644P(diffrent to the bootloader) it work perfectly)
When i programming with SPI, I can't choose 644P(compiling ok bu error uploading), when i choose 644A i have erreur compiling of "serial1 unknowing".

Not all versions of 644 have 2 serial ports. The devices have different signature bytes as well:

ATmega164A/164PA/324A/324PA/644A/644PA/1284/1284P DATASHEET:

ATmega644A 0x1E 0x96 0x09 (I believe 2 ports)
ATmega644PA 0x1E 0x96 0x0A (I believe 2 ports)

ATmega164P/V-324P/V-644P/V DATASHEET:

ATmega644P and PV 0x1E 0x96 0x0A (I believe 2 ports)

ATmega644/V Datasheet:
ATmega644 0x1E 0x96 0x09 - One Serial Port per the datasheet
But same signature bytes as the 644A, so perhaps A only has 1 also?

Thx for your response but my chip has two SPort “” the probleme is bootloader uploaded on it is for 644A and this chip has One serial port, but when i uploaded programme on it i use 644p and compiling accept Serial1 and it work perfectly. the first and second serial port work great (Bootloader 644A, programming(serial Tx,Rx) 644P) i need 3rd Serial port and when i use SoftwareSerial, Rx doest not work just Tx is working).