Has phosphodiesterase (PDE) activity against cyclic-di-AMP (c-di-AMP) and to a much lesser extent against cyclic-di-GMP (c-di-GMP) in the DHH/DHHA1 domains. Also has ATPase activity, probably via the GGDEF domain. May monitor cellular heme or NO levels. 3',3'-c-di-AMP + H2O = 5'-O-phosphonoadenylyl-(3'->5')-adenosine + H(+) Binds 1 heme b per subunit. Probably binds 2 Mn(2+) per subunit. The PAS-like domain (residues 55-162) dimerizes. Binds heme b via the PAS-like domain. Belongs to the GdpP/PdeA phosphodiesterase family.