Remote Processing RPC-52 - Manual (Page 15)

CHAPTER 5 RAM MEMORY
Page 13
Figure 5-1 RAM chip, W4 jumper, & battery
INTRODUCTION
RPC-52 m odels are available with 32K or 128K of
battery backed RAM . RA M may be changed at any
time. RA M is in socket U3.
RAM is automatically backed up when it is installed.
The battery is shared with the clock and controlled by
the reset/watch dog timer. Battery life will depend upon
R A M s iz e , it s p o we r c on s um p ti on , a n d a m o un t o f ti m e
t he b oa r d is o pe r a ti ng . G e ne r a ll y, a b at te r y li fe f ro m 5
to 10 years can be expected.
This chapter discusses changing RAM, saving and
retrieving variables, r unning assembly language
programs, and battery maintenance. Figure 5-1 shows
the location of U3, jumper W 4, and the battery.
Increasing RAM size does not increase the program size
RPBASIC-52 can handle. Maximum program and
variable size is 60K. Additional RAM does increase the
amount of space available for PEEK and POKE storage.
CHANGING MEMORY
Different types of memory can be installed at any time.
RPC-52 models come with either 32K or 128K of RAM
installed. Up to 512K can be installed.
To change a mem ory chip, you need to rem ove the
original chip, install the new one, and set jumper W 4.
To install a new memory chip:
1. Turn off power to the RPC-52.
2. Remove the mem ory chip from U 3.
3. Orient the chip so pin 1 is towards the card edge.
If installing a 32K RAM , place the chip at the
bottom of the socket (m emor y chip pin 14 go es into
socket pin 16). The top two socket pins in each row
will be empty.
If installing a 128K or 512K, install the chip into the
socket.
4. Check and change , as n ecessar y, jum per W 4 to
conform to the new mem ory.
RAM size Jumper
32K [2-3]
128K [2-3]
512K [1-2]
BATTERY BACKUP
The RPC -52 battery operates the clock and backs up the
RAM when power is off. Battery life will depend upon
RAM size, type, and time the RPC-52 has power applied
to it. You can expect the battery to last between 5 to 10
years.
NOTE: Do not place the RPC-52 circuit on a metal
surface, even w ith the power off, without
standoffs. Voltage is present on the circuit side
of the board and it is possible to short out the
battery supply throug h the circuit traces.
Battery voltage is approximately 2.7 volts. The voltage
is measured by placing a volt meter between ground and
the battery clip.
The battery may be re placed by the following type or
equivalent:
Panasonic BR2325
To replace the battery, lift up the holder and push the
battery from behind. To install, simply reverse the
proced ure. The batter y may be replace d while pow er is
on. If you rep lace the batter y with pow er off, be sure to
reset the da te and time. Also, data stored in RAM will
be lost.