Measurement Computing TempBook rev.3.0 - Manual (Page 83)

TempBook User’s Manual tbkCommand Reference (Standard API) 9-23
tbkSetProtocol
DLL Function int tbkSetProtocol( int protocol)
C tbkSetProtocol(int protocol);
QuickBASIC BtbkSetProtocol% (ByVal protocol%)
Visual Basic VBtbkSetProtocol% (protocol%)
Turbo Pascal tbkSetProtocol( protocol:integer ):integer;
Parameters
protocol One of the predefined protocol codes listed below (additional protocol codes may be described in the
README file).
Name
Description Value
TbkProtocol8 8-bit I/O 1
TbkProtocol4 4-bit I/O 2
TbkProtocolFPort Far Point F/Port EPP Interface 10
TbkProtocolSL 82360 SL EPP Interface 20
TbkProtocolSMC666 SMC 37C666 EPP mode 30
TbkProtocolEPPBIOS EPP bios mode 40
TbkProtocolPastEPP WBK20/21 Fast EPP mode 50
Returns An error number, or 0 if no error.
See Also tbkInit, tbkGetProtocol
Program References
tbkSetProtocol specifies to the TempBook/66 driver the type of parallel-port implementation
and protocol that is available on the computer. The driver then attempts to configure the computer
and the TempBook/66 to communicate using the specified protocol. Since establishing the protocol
may affect the settings of the TempBook, tbkSetProtocol should only be invoked immediately
after tbkInit has established communications with and reset the TempBook. Switching protocols
during normal TempBook/66 operation is not recommended.
Two types of parallel port implementations are supported by the TempBook: standard and enhanced.
Standard parallel ports, using the TempBook/66 manufacturer’s proprietary protocols, are capable of
receiving data either 4 or 8 bits at a time. When possible, 8-bit operation is preferred (it is much
faster), but not all standard parallel ports support 8-bit data reception.
Enhanced parallel ports (EPP) include extra hardware that increases the rate of data transfer to 3 to
10 times the rate of a standard parallel port. Unfortunately, not every computer includes EPP
capability and attempting to use EPP on an incompatible computer may cause the TempBook/66
driver to access I/O locations which are not part of the printer port interface. Such accesses may
interfere with other operations and cause the computer to operate incorrectly. For this reason, EPP
operation must be explicitly requested by the program.
When the TempBook/66 is initialized by tbkInit, it is initially configured for a standard parallel
port protocol: either 8-bit, if possible, or the slower 4-bit protocol. After tbkInit has completed,
tbkSetProtocol
may be used to switch to another supported protocol.
If tbkSetProtocol is unable to establish communications using the specified protocol, then it
will try to establish communications using the standard port protocols, first 8-bit, then the slower 4-
bit. In such an event, tbkSetProtocol will not return an error indication unless it is unable to
establish any protocol.
In any case, tbkGetProtocol may be used to check the current operating protocol.