1.2 Added/Modified Pin Functionality

There are two package types that are compatible with ATmega48A/88A/168A and ATmega48PB/88PB/168PB. This section will compare the pin-out of the TQFP package type. For the other compatible package type, MLF/VFQFN, refer to the data sheet chapters "Ordering Information" and "Packaging Information".

ATmega48PB/88PB/168PB introduces four additional GPIO pins; PORTE [3:0]. The different pins are described in Table 1-1 and the pin-out for each device are shown in Figure 1-1 and Figure 1-2.

The 32-pin MLF/VQFN pin-out can be found in the Pin Configurations section in the ATmega48PB/88PB/168PB data sheet.

Figure 1-1.  ATmega48A/88A/168A - 32-Pin TQFP
ATmega48PA/88PA/168PA - 32-pin TQFP
Figure 1-2.  ATmega48PB/88PB/168PB - 32-Pin TQFP
ATmega48PB/88PB/168PB - 32-pin TQFP

GPIO pins PE2 and PE3 are added to Pin19 and Pin22. PE2 and PE3 are multiplexed with ADC6 and ADC7.

Pin3 (GND) and Pin6 (VCC) are replaced by PE0 and PE1 respectively. PE0 is multiplexed with ACO.

Table 1-1. Pin Functionality Difference
32-Pin TQFP PackageATmega48A/88A/168AATmega48PB/88PB/168PB
Pin3GNDPE0/ACO
Pin6VCCPE1
Pin19ADC6ADC6/PE2
Pin22ADC7ADC7/PE3
CAUTION: To use the ATmega48PB/88PB/168PB device as a drop-in replacement for the ATmega48A/88A/168A the following conditions must meet:
  • Pin 3 - If connected to GND, the pin must not be actively driven or ACO must not be enabled.
  • Pin 6 - If connected to VCC, the pin must not be actively driven.