User`s guide

6. THE ROM MEMORY BLOCK
The GAL programs support a variety of alternative memory maps using the jumpers CFG0,
CFG1, and CGF2. See section 5.4 to determine the memory map configuration you wish
to use. The following sections describe how to select which chips to use in the ROM
memory block, and how to download to, and run programs from, the ROM block.
6.1 Configuring U7 and U8
6.1.1 Chip Selection
The RMB-167i has two sockets marked U7 and U8 which are intended for a variety of non-
volatile devices. U7 and U8 are considered to be the ROM block of memory no matter
which type of devices are selected. Typically 27C256-type 32K EPROMs, 62C256-type
battery-backed RAMs or 28C256-type EEPROMs are used. Note that RAMs and
EEPROMs have the same pinout and while it is possible to populate the sockets with a mix
of these two devices it is recommended that you use the same device and speed in both
sockets to insure smooth program operation. It is not possible to populate an EPROM in
one socket and a RAM or EEPROM in the other since the pinouts of the devices are
different. When downloading programs to these devices the odd bytes are loaded into U8
and the even bytes are loaded into U7.
6.1.2 Jumper Selection
The jumpers located next to U8 select which memory devices are to be used in U7 and U8.
One end of the jumpers is marked RAM and the other end is marked ROM. Note that
since RAMs and EEPROMs have the same pinout the jumper setting is the same for these
devices. If U7 and U8 hold RAM or EEPROM devices, insert two jumpers, so that the
center posts of both jumpers are connected to the end posts marked RAM. If U7 and U8
hold EPROMs, insert the two jumpers so that the center posts are connected to the end
posts marked ROM.
6.2 Downloading and Running Programs in ROM
The method of loading programs into the ROM block varies depending on the type of
devices used. The following are the three options available to the user.
6.2.1 RAMs
Both battery-backed RAMs and static RAMS may be used in U7 and U8. When using
RAMs there are two things to remember, any program in a static RAM will be lost if the
power to the board is disconnected, and U7 and U8 are the ROM memory block even if
populated with RAMs. The procedure for downloading to the two types of RAMS is the
same.
Downloading programs
1. With the power disconnected populate U7 and U8 with the RAMs.
2. Insert the two jumpers by U8 in the RAM position.
3. Connect the power to the board.
4. Bootstrap the board as usual.
5. Insert jumpers at CFG0, CFG1, and CGF2 to select the alternate memory map you
wish to use. (See section 5.4)
6. Select the TTY | Download menu item. Choose your program from the list of files.
7. Press OK to download the file.
Running the program with the starting address above zero.