Cassette
The cassette input and output is based on square wave signals. The cassette out is generating a square wave signal by switching the Q flag between 0 and 1. The cassette input is linked to the EF2 flag.
Every bit is generated either by a high or low square tone to represent a 0 or 1. Where the start tone is a long square wave with a high tone, followed directly by all program data.
LOAD
To load a file into the Nano, press 'B' and then press play and after that (as soon as possible) press the number of 'blocks of 256 bytes' you want to load (1 to F).
SAVE
To save a file from the Nano, press the record and then press 'F' and the number of 'blocks of 256 bytes' you want to save (1 to F).