BCI Capnocheck Plus - Display and Speaker Control

Chapter 3: Capnocheck Plus Circuit Description
The I/O address space is divided according to the following table:
VO Address Space Device
0..1FFF Used by Z180 for internal registers
2000.. 3FFF External VO
4000 .. 5FFF RAM Page Register
6000 .. 7FFF Display Select
8000 .. 9FFF Volume Control Select
A000 .. FFFF Not used
External I/O is the only VO select available outside the FPGA, all others are
used inside the chip.
Display Controller.
Vacuum Fluorescent Display Module is used in the Monitor to display
graphical and numerical information. The Display has its own controller board
- which accepts data in parallel 8-bit format in the form of Commands (signal
AO on the Display communication connector J2 is log. 1) and Data (signal AO
on the Display communication connector J2 is log. 0). Bi-directional data bus
buffer US is used to pass data from the Display board to the microprocessor
and from the microprocessor to the Display Board. All signals to control U5
and Display Board are generated inside FPGA U4:
ZUR
— jr 一
LL...
3-4 Capnocheck Plus Service Manual