Rockwell Automation 1747-PCIS API Software - Open Controller - Manual (Page 15)

Publication 1747-UM002A-US-P - June 2000
Overview 1-3
API Software for Windows NT
The Windows NT API supports any programming languages that use
the Win32 _stdcall calling convention for application interface
functions. The Windows NT API function names are exported from a
DLL in undecorated format to simplify access from other
programming languages.
The Windows NT API software consists of two main components:
•
the OCdriver (depending on your application, either 1746 I/O
PCI Interface device driver or Open Controller device driver)
•
the API library, which is a DLL (dynamically-linked library)
The Windows NT API library is a DLL and must be installed on the
system in order to run an application which uses it. The Windows NT
API accesses the scanner via the driver created for the bus interface
The driver:
•
allocates resources (interrupt and memory window)
•
initializes scanner hardware
•
provides access to the scanner’s dual port RAM
•
services interrupts from the scanner (priority messages)
•
provides access to SRAM
When the OCdriver is loaded it tries to allocate an interrupt and a
memory window for the memory and interrupt that were allocated
using the settings by the PCI bus at power-up for the dual port RAM.
If IRQ 11 and address oxC8000 are not available (i.e., another device
already allocated the resource), OCdriver tries to allocate any resource
for which the scanner hardware can be configured (IRQ 10, 12, and
15; memory address 0xCA000 - 0xDE000). OCdriver fails to load if an
interrupt and memory window cannot be allocated.
Once an interrupt and memory window are allocated, OCdriver
initializes the scanner hardware to match the allocated resources.
IMPORTANT
Only access the OCdriver through the API library
functions.