GTCO Summagrid IV - Users Guide Part 2 - Manual (Page 23)

Summagrid IV 23
Chapter 3 Guidelines for Writing a Software Driver
If the Summagrid IV is connected to a computer, rather than to a terminal, the computer
must have a driver for the tablet. The driver is a software subroutine that collects and
decodes Summagrid IV reports for use by another (master) program. This chapter provides
some guidelines, in the form of flowcharts, for writing a driver.
The flowcharts are for a Summagrid IV using the Summagraphics UIOF packed binary
report format. The steps are general for any set of operating characteristics.
NOTE: In the context of these charts, normalize means to combine the coordinate bytes
into the format required by the user’s master program.
3.1
3.1.1
3.1.2
3.1.3
3.1.4
3.1.5 Flowcharts for Writing Drivers
General Flowchart for Master Program to Read and Process Digitizer
Reports
Detail A: Get Binary Format Report
Detail B: Get Binary Format Report, Poll/Remote Mode or Stream Mode
Detail C: Get Byte from Tablet
Detail D: Normalize Bytes into X and Y Coordinates, Switch and
Proximity Information 24
24
25
26
27
28