The TSC Text Processor was available for both the 6800 and 6809 version of FLEX. (There was even a version for non disk systems.) The manual here is a copy of the Version 2.4 for the 6809 but it is almost identical to Version 2.3 for the 6800.
User's Guide (91k PDF)
User's Guide - Microsoft Word File (48k ZIP)
Michael Holley's SWTPC Collection Home Page