J3 Boot Rom Write Protection - Motorola MBX Series Installation And Use Manual

on J1 pins 2 and 3 designates an external battery source via utility
connector #1. (See

J3 Boot ROM Write Protection

Flash memory on the MBX series embedded controller consists of one
bank of four 32-pin PLCC Flash devices soldered directly to the board.
Flash memory provides 2MB (in entry-level versions) or 4MB (in standard
versions) of storage. EPPCBug firmware takes up 512KB (128K words) of
space; the remainder of Flash memory is available for user applications.
The firmware resident in Flash memory is originally loaded at the factory,
but the Flash contents can be reprogrammed if necessary.
For purposes of reprogramming Flash, the MBX includes a 32-pin socket
(XU1) in which firmware programmers can install a removable boot ROM
device. To prevent inadvertent overwriting of the Flash memory used in the
boot ROM, header J3 provides write protection for the device installed in
XU1.
http://www.motorola.com/computer/literature
Connecting an External Battery on page
J1
1 2 3
Internal Battery Backup
(factory configuration)
J3 Boot ROM Write Protection
1-10.)
J1
1 2 3
External Battery Backup
2146 9802
6
6-5