What was found
AIRCRAFT GROUNDED: AN EMERGENCY DECLARED AT INITIAL CRUISE, RECEIVED ECAM CABIN PRESSURE SYS 1 FAULT FOLLOWED SHORTLY BY ECAM CABIN PRESSURE SYS 1 & 2 FAULT. CREW REPORTED CABIN PRESSURIZATION OPS IN MANUAL MODE OKAY. FLT CREW REPORTED DURING INITIAL DESCENT INTO MIA, INCREASED WORKLOAD ASSOCIATED WITH MANUAL PRESSURE MANAGEMENT INCLUDING POWER CHANGES & DESCENT PLANING MADE MX OPTIMAL CONTROL MORE CHALLENGING. CREW DECLARED PAN-PAN & REQUESTED DIRECT ROUTING TO MIA, CONTINUOUS DESCENT TO REDUCE WORKLOAD & MAINTAIN STABLE PRESSURE CONTROL. ACFT DESCENDED & LANDED IN MIA SAFELY WITHOUT INCIDENT. MX CLEARED FAULT IAW AMM 21-31-00 & REPLACED OUTFLOW VALVE IAW AMM 21-31-51. A SAT OPS CHECK ACCOMPLISHED.