  The intrinsic performance of the ATLAS barrel and extended barrel
calorimeters for the measurement of charged pions is presented. Pion energy
scans (E = 20, 50, 200, 400 and 1000 GeV) at two pseudo-rapidity points ($\eta$
= 0.3 and 1.3) and pseudorapidity scans ($-0.2 < \eta < 1.8$) with pions of
constant transverse energy ($E_T = 20$ and 50 GeV) are analysed. A simple
approach, that accounts in first order for non-compensation and dead material
effects, is used for the pion energy reconstruction. The intrinsic performances
of the calorimeter are studied: resolution, linearity, effect of dead material,
tails in the energy distribution. The effect of electronic noise, cell energy
cuts and restricted cone size are investigated.
