NCR RealPOS 70 - Cash Drawer Hardware;Firmware Interfaces

12-6 Chapter 12: Cash Drawer Interface
Hardware/Firmware Interfaces
Insomepreviouslysupportedmodels,nopreliminaryinteractionwith
thehardwarewasrequiredtodeterminetheportaddress(s)usedfor
communicationwiththecashdrawer;thesedatawereinsteadobtained
fromtheregistry.Forthe7402,theportaddressissetdynamicallyby
theBIOSandhencethehardwaremustbe
queriedtoobtainthis
information.Thisdictatestheneedforthegenerationofa
configurationcycleasdescribedpreviously.
Configurationmechanismoneutilizestwo32bitI/Oportslocatedat
addresses0x0CF8and0x0CFC.Thesetwoportsare:
• 32‐bitconfigurationaddressport‐occupyingI/Oaddresses0x0CF8
through0x0CFB.
•
32‐bitconfigurationdataport‐occupyingI/Oaddresses0x0CFC
through0x0CFF.
AccessingaPCIfunction’sconfigurationportisatwostepprocess:
• Writethetargetbusnumber,physicaldevicenumber,function
numberanddoublewordnumbertotheconfigurationaddressport
• PerformanI/Oreadfromorawriteto
theconfigurationdataport.
TheICH4ConfigurationAddressRegistershouldbedefinedas
follows:
• ConfigurationSpaceMappingenabled
• Busnumber0
• Devicenumber31
• Functionnumber0
• GPIObaseregisteroffsetaddress0x58