Here is variant AtMega8 + L298 and SourceCode with "Dead-Time"=1 mks.
I this did not check so do not guarantee work. For initial check possible to use SourceCode Servo_AtMega_TimerInt. With this code must work all. Afterwards you programme SourceCode Servo_Mega8_L298. If that that will not work, write - try to correct.
Diodes VD1-VD4 better to use UltraFAST or Shottkydiodes.
Possible this driver on L298 http://www.ikalogic.com/shm_hb_l298.php will better work.