NCR RealPOS 70, Руководство пользователя

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12-4 Chapter 12: Cash Drawer Interface
Component Architecture
The developer should provide a description, either textually or
diagrammatically (i.e., block diagram), of how the components of the
module subsystem interact in this sub ‐ section.
The member function Initialize() is subsequently called to open the
NCR Windows NT port driver (if applicable) and perform other
initialization tasks. Then, the device’s OpenPort() member function is
called to make the device available, at which time QueryConf() is called.
Once the device has been configured, the member functions
OpenDrawer(), GetDrawerStatus() and SetState() can be called to interact
with the cashdrawer. These methods themselves invoke the member
functions WriteIOPort() and ReadIOPort() to actually send and receive
data to the cashdrawer via the port addresses obtained in QueryConf() .
Code Changes
Following is an enumeration of the code changes needed to support the
7402:
The interface of the new device supports two separate fields for GPIO
select port address (read/write) and solenoid and status bit port
address (read/write). The chip GPIO bits must be selected for use as
GPIO and as either input or output.
It is desired that the driving circuit be disabled at power on and when
not actively driving the solenoid. Two output control implementations
will be used:
1. Use the m_nIOPort_Selec t address register to set the solenoid bit to
an output function before driving the bit high using m_nIOPort , set
the solenoid bit low after the charging time and then setting the bit
function to input using m_nIOPort_Select .