FRAM71B
User’s Manual
FRAM71B 1.00
- 10 -
©Hans Brueggemann, 2016
8 Jumpers
Six jumper positions on FRAM71B control its start-up behavior, SYSRAM availability and ROM
definition. Using the default settings will put FRAM71B into "RAM-only” mode:
Picture 1: FRAM71B DEFAULT Configuration
8.1
CN2-5: HARDCONF_C0_E0000
"Configure chip_0 to address H_0xE0000 and make it hard-configured ROM"
Default: not set (jumper removed)
If set, FRAM71B will re-allocate chip_0 as "hard configured ROM" to H_0xE0000. This feature
is used in conjunction with the hard configured part of a FORTH/Assembler ROM image. If
you don’t plan to use FORTH, leave this jumper removed.
8.2 CN2-4: ENA_SYSRAM_WRT
"Enable writes to SYSRAM areas"
Default: not set (jumper removed)
If set, FRAM71B will enable write access to F_0x00000 - F_0x1FFFF on both TOP and BOT
FRAM at the same time, regardless of CN2-1. Useful to protect the SYSRAM area of
FRAM71B against accidential overwrites. The red indicator in the front bezel will be on while
this jumper is set. During write operations to the SYSRAM area, the indicator will flash.
8.3 CN2-3: DIS_HPBUS_WRT
"Disable all writes to the HP-71B bus"
Default: not set (jumper removed)
If set, FRAM71B will become invisible to your HP-71B, but will still accept changes to its con-
figuration area (C_0x2C000 - C_0x2C01F). This is useful if your HP-71B does no longer re-
spond to a RESET [ON]/[/],[3] and you need to get it back to a known state.
DIS_HPBUS_WRT does not disable SYSRAM (F_0x00000 - F_0x1FFFF). Thus, an alternate O/S
selected by J1 stays in effect even if all FRAM is disabled.
CN2-2:DIS_OUT_wh_CONFIG
CN2-3:DIS_HPBUS_WRT
CN2-4:ENA_SYSRAM_WRT
CN2-5:HARDCONF_C0_E0000
J1:ENA_SYSRAM
CN2-1:SLCT_TOP(Option)
