<parts>
  <regblock  name="I/O_REG" start="0x0020" end="0x005F" offset="32">
    <register  name="ADCSRB"  addr="0x0003" mask="01000111" 
               bits="ADTS0,ADTS1,ADTS2,0,0,0,ACME,0" />
               
    <register  name="ADCL"    addr="0x0004" bits="" />
    <register  name="ADCH"    addr="0x0005" bits="" />
    <register  name="ADCSRA"  addr="0x0006" 
               bits="ADPS0,ADPS1,ADPS2,ADIE,ADIF,ADATE,ADSC,ADEN" />
               
    <register  name="ADMUX"   addr="0x0007" mask="01100011" 
               bits="MUX0,MUX1,0,0,0,ADLAR,REFS0,0" />
               
    <register  name="ACSR"    addr="0x0008" mask="11011011" 
               bits="ACIS0,ACIS1,0,ACIE,ACI,ACO,ACBG,ACD" />
               
    <register  name="DIDR0"   addr="0x0014" mask="00111111" 
               bits="AIN0D,AIN1D,ADC1D,ADC3D,ADC2D,ADC0D,0,0" />
               
    <register  name="PCMSK"   addr="0x0015" mask="00111111" 
               bits="PCINT0,PCINT1,PCINT2,PCINT3,PCINT4,PCINT5,0,0" />
               
    <register  name="PINB"    addr="0x0016" />
    <register  name="DDRB"    addr="0x0017" />
    <register  name="PORTB"   addr="0x0018" />
    <register  name="EECR"    addr="0x001C" mask="00111111" 
               bits="EERE,EEPE,EEMPE,EERIE,EEPM0,EEPM1,0,0" />
               
    <register  name="EEDR"    addr="0x001D" />
    <register  name="EEARL"   addr="0x001E" />
    <register  name="WDTCR"   addr="0x0021" 
               bits="WDP0,WDP1,WDP2,WDE,WDCE,WDP3,WDTIE,WDTIF" />
               
    <register  name="CLKPR"   addr="0x0026" mask="00001111"
               bits="CLKPS0,CLKPS1,CLKPS2,CLKPS3,0,0,0,CLKPCE" />
               
    <register  name="GTCCR"   addr="0x0028" mask="10000001"
               bits="PSR10,0,0,0,0,0,0,TSM" />
               
    <register  name="OCR0B"   addr="0x0029" />
    <register  name="DWDR"    addr="0x002E" />
    <register  name="TCCR0A"  addr="0x002F" mask="11110011"
               bits="WGM00,WGM01,0,0,COM0B0,COM0B1,COM0A0,COM0A1" />
               
    <register  name="OSCCAL"  addr="0x0031" />
    <register  name="TCNT0"   addr="0x0032" />
    <register  name="TCCR0B"  addr="0x0033" mask="00001111"
               bits="CS00,CS01,CS02,WGM02,0,0,FOC0B,FOC0A" />
               
    <register  name="MCUSR"   addr="0x0034" mask="00001111"
               bits="PORF,EXTRF,BORF,WDRF,0,0,0,0" />
               
    <register  name="MCUCR"   addr="0x0035" mask="01111011"
               bits="ISC00,ISC01,0,SM0,SM1,SE,PUD,0" />
               
    <register  name="OCR0A"   addr="0x0036" />
    <register  name="SPMCSR"  addr="0x0037" mask="00011111"
               bits="SELFPRGEN,PGERS,PGWRT,RFLB,CTPB,0,0,0" />
               
    <register  name="TIFR0"   addr="0x0038" mask="00001110"
               bits="0,TOV0,OCF0A,OCF0B,0,0,0,0" />
               
    <register  name="TIMSK0"  addr="0x0039" mask="00001110"
               bits="0,TOIE0,OCIE0A,OCIE0B,0,0,0,0" />
               
    <register  name="GIFR"    addr="0x003A" mask="01100000"
               bits="0,0,0,0,0,PCIF,INTF0,0" />
               
    <register  name="GIMSK"   addr="0x003B" mask="01100000"
               bits="0,0,0,0,0,PCIE,INT0,0" />
               
    <register  name="SPL"     addr="0x003D" />
  </regblock>
  <stack  spreg="SPL" increment="postdec" />
</parts>
