Zilog Z80195 - Manual (Page 16)

Z80185/195 D EVELOPMENT K IT
U SER ' S M ANUAL
2-8 UM951800100
Z ILOG
SETTING UP THE PARALLEL CHANNEL (Optional)
(Skip this section if you are not using the 185’s parallel port.)
Host
If you are using the 185 board to act as a Host on the parallel port, such as connecting it to a printer,
make sure there is a shunt block on J5 and not on J6.
Peripheral
If you are using the 185 board to act as a Peripheral on its parallel port, such as connecting it to a
the parallel port of a PC, make sure there is a shunt block on J6 and not on J5.
Notes:
1. The shunt block on J5 or J6 configures serial resistors on outputs and pull-up resistors on inputs,
among the nine parallel control signals: nAck, Busy, PError, Select, nFault, nAutoFd, nStrobe,
nSelectIn, and nInit. The shunt block also controls the state of the PERIPHI signal on the J3 and
J4 connectors, and of the HOSTHI signal on J4.
PERIPHI and HOSTHI are also connected to J14-6 and J14-3 respectively, from which one of them
can be connected to a 185 input such as PIA16 or PIA15, so that software on the 185 can sense
which shunt block is installed and set the mode of the parallel port to Host or Peripheral
accordingly. If you have software that provides such automatic mode setting, consult its
documentation for the proper jumper setting.
2. You can also fill the J5 or J6 jumper block (but not both) with individual shunts.
3. Connect your parallel cable to one of J2, J3, or J4. The DB-25 J2 is typically used if you want the
board to act as a Host using a traditional parallel cable. The full-size 36-pin “Centronics”
connector J3 is typically used if you want the board to act as a Peripheral using a traditional parallel
cable. The half-size 36-pin connector J4 is recommended by the 1284 draft for new Host and
Peripheral designs.
OTHER JUMPER OPTIONS
EPROM Size
J1 should be set according to the size of the EPROM installed in the U2 socket:
Jumper J1-1 to J1-2 for 27256 (or smaller) EPROM
Jumper J1-2 to J1-3 for 27512 EPROM