Zenith Data Systems Z-100 Series Installation Manual page 59

Page
5.9
Card/Circuit Description
Typically, the CPU writes data into a memory which is dedicated to the
display. The CRTC then controls the transfer of that data from the video
memory to the display and provides the sync signals to the CRT.
The pinout of the 6845 is shown in Figure 5.2. The pins have the functions
shown in Table 5.3.
Figure 5.2. 6845 Pinout