Eagle CAD: 1. CPU/ROM/RAM Board
Eagle CAD 2: Reset, NMI, Halt Circuits
Eagle CAD 3: Right-angle Male Bus Connector
Eagle CAD 4: A Possible PCB Layout
Bill of Materials
BOM:
CPU/ROM/RAM Bd.
|
System
Overview
The
ZB64EC basic Z80 system is modular and is composed of 4 boards:
-
an extendable 6-slot backplane
-
a CPU/ROM/RAM board
-
a Bank0 ROM-RAM switch board
-
a UART board for terminal communication
Additional boards can be added to the system, including a bus
extension board. See the
ZB64EC-bus Z80 MBC menu for the current list.
ZB64EC Z80
System Features
1)
Essential system functions have been distributed over 3 boards. The
boards are 4" wide x 3" high (102 x 76mm). This makes for easier
troubleshooting as well as learning how the system and bus
communication works.
2)
12 user bus lines, USER_A to USER_L, have been added for
customization. These are in addition to the BANK_0 to BANK_3 and
IO_0 to IO_3 bus lines created by
Peter Murray of
39k.ca for his
M62-bus based Z80 SBC. Each USER_x
bus line can be terminated high (10K) or low (4.7K) or not at all.
3)
Each bus line is available at each slot via jumpers. It is possible
to use a single bus line completely across the backplane, or it can
be used many times for
different functions by only jumpering the needed bus sections.
4)
You can design your own boards to add them to the system, and use
any of the available bus lines or bus line sections.
Minimalist Design?
Only
the essential functions are designed into each board.
The
RESET circuit used by
the Z80 needs to be inverted and carried over the bus to the RESET
input of the UART. We see that as bus line USER_F1 in the Reset
section of Eagle CAD 2:
Reset, NMI, Halt Circuits
It's listed at the bottom of the schematic.
I
see the schematics. Where is the Bill of Materials parts list?
The
BOM is at the bottom of the adjacent panel.
How big is the ZB64EC Z80 CPU board and what will the printed circuit boards look like?
The
ZB64EC CPU board measures 100mm x 76mm (4" x 3"). Click on the
adjacent thumbnail
below to see a possible parts layout for your design for the
CPU/ROM/RAM board.
Note: M62 Bus is copyrighted by
Peter
Murray of Murray Electronics,
http://www.39k.ca |