RAM MEMORY SECTION 5
Page 5-1 RPC-320
Figure 5-1 RAM and W1 jumper location
INTRODUCTION
32K, 128K, or 512K of RAM may be battery backed on
the RPC-320. RAM size can be changed at any time.
RAM is in socket U5.
RAM is backed up when a DS1216DM is installed.
Battery life depends upon RAM size, its power
consumption, ambient temperature, and amount of time
the board is operating. Generally, a battery life of about
3 to 5 years is e xpected. Oper ating the board at 50 °C
reduces battery life by 1/2.
The DS1216DM is also a real time clock. Thus, DATE
and TIM E functions and commands are available when it
is installed. See Chapter 7 for more information.
This chapter discusses changing RAM, saving and
retrieving variables, running assembly language
programs, and battery condition. Figure 5-1 shows the
location of U3 and jumper W1.
Increasing RAM size does not necessarily 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-320 models come with either 32K or 128K of RAM
installed. Maximum is 512K.
To change a memory chip, you need to rem ove the
original chip, install the new one, and set jumper W1.
To install a new memory chip:
1. Turn off power to the RPC-320.
2. Remove the memory chip from U5.
3. Orient the chip so pin 1 is towards the inside.
If installing a 32K RAM, place the chip at the
bottom
of the socket (m emory chip pin 1 goes into
socket pin 3). The top two socket pins in each row
are empty.
If installing a 128K or 512K, install the chip into the
socket.
4. Check and change, as necessary, jum per W1 to
conform to the new memory.
RAM size Jumper W1
32K [1-2]
128K [1-2]
512K [2-3]
BATTERY BACKUP
An optional battery backup module may be installed.
Principal is the same as installing a RAM chip.
WARNING:
An additional modification must be performed to the
DS1216DM module when a 512K RAM is installed.
Contact Remote Processing for details.
To install a module:
1. Remove the RAM IC in U5.
2. Install the DS1216DM in U5.
3. Re-install the RAM chip into the top of the module.
Checking the battery
Battery voltage is approximately 3.0 volts, measured
between pin 16 (ground) and 30 (128K RAM), 14 and 28
(32K RAM), or 16 and 32 (512K RAM) on the IC itself
(not the circuit side of the board). Be sure to power up
the RPC -320 once to activate the battery backup cir cuit
in the module.
