Pseudo Rom Pin 1 Select Header (W2); Pseudo Rom Package Size Select Header (W3); Chapter 3 Memory Configuration (Continued) - Motorola M68MPFB1632 User Manual

MEMORY CONFIGURATION

3.2.2.1 Pseudo ROM Pin 1 Select Header (W2)

Jumper header W2 configures the signal for pin-1 of a 32-pin memory devices in the pseudo
ROM sockets (U2 & U4). (28-pin devices installed in U2 & U4 are not affected by the setting of
W2.) The drawing below shows the factory configuration: the fabricated jumper between pins 1
and 2. With the jumper between pins 1 and 2, pin-1 of the pseudo ROM sockets is a standard
address line. The alternate configuration (jumper between pins 2 and 3) connects VPP to pin-1 of
the pseudo ROM sockets and lets you program flash EEPROM memory devices. To activate
VPP, switch S1 must be set to ON (refer to paragraph 5.2.2). If S1 is OFF and W13 is installed,
+5Vdc appears on W2 pin-3. If S1 is OFF and W13 has no jumper installed, then W2 pin-3
floats.
W2
1 2 3
Address
+12V
Fabricated
Jumper

3.2.2.2 Pseudo ROM Package Size Select Header (W3)

Jumper header W3 configures the MEVB memory device package size for memory devices in
the pseudo ROM sockets (U2 & U4). The drawing below shows the factory configuration: the
fabricated jumper between pins 1 and 2 for 28-pin packages. When using 32-pin memory devices
in the pseudo ROM sockets move the jumper to pins 2 and 3. W3 connects either device power
or an address signal for the appropriate device.
W3
1 2 3
28 Pin 32 Pin
Fabricated
Jumper
M68MPFB1632/D 3-13