A. Board Configuration
ÛZIATECH
92
W9 (Flash Write Protect)
Installing W9 write protects the contents of the flash memory; removing W9 makes the
flash writable.
W9
Function
In
Flash is write protected
Out
Flash is writable
J12 (Port 80 Decode)
Installing a jumper across pins 1 and 2 on J12 enables the Port 80 diagnostic codes.
These codes are sent to connector J5 and are for debugging purposes only.
J12 also serves as the In-System Programming Connector.
J12 Pins 1 and 2
Function
Jumpered
Port 80 codes sent to PIO7-PIOO (J5, pins 33-48)
†
Not jumpered
Normal operation
RP1, RP2 (Permanent Master Pullups)
Resistor packs RP1 and RP2 serve two related purposes, detailed below.
1.
Permanent Master Configuration
. When RP1 and RP2 are installed, the ZT 8907
is configured as a Permanent Master and pulls up the STD 32 bus signals. In a
STAR SYSTEM, only one CPU (the Permanent Master) is allowed to pull up the
STD 32 bus signals.
2.
CLOCK* and SYSRESET*
. When RP1 and RP2 are installed, the ZT 8907 drives
the CLOCK* and SYSRESET* signals; removing RP1 and RP2 inhibits the CPU
from driving the CLOCK* and SYSRESET* signals. Only the Permanent Master is
allowed to drive these signals.
†
Factory default configuration