Comparison Between Processors

The ATmega48PB/88PB/168PB differ only in memory sizes, boot loader support, and interrupt vector sizes. The table below summarizes the different memory and interrupt vector sizes for the devices.

Table 1. Memory Size Summary
Device Flash EEPROM RAM Interrupt Vector Size
ATmega48PB 4KBytes 256Bytes 512Bytes 1 instruction word/vector
ATmega88PB 8KBytes 512Bytes 1KBytes 1 instruction word/vector
ATmega168PB 16KBytes 512Bytes 1KBytes 2 instruction words/vector

ATmega88PB/168PB support a real Read-While-Write Self-Programming Mechanism (SPM). The SPM instruction can only execute from the separate Boot Loader Section. In ATmega48PB there is no Read-While-Write support and no separate Boot Loader Section. The SPM instruction can execute from the entire Flash.