Remote-processing RPC-52 Manuel d'utilisateur télécharger pdf (Page 15)

CHAPTER 5 RAM MEMORY

Page 13

Figure 5-1 RAM chip, W4 jumper, & battery

INTRODUCTION

RPC-52 models are available with 32K or 128K of

battery backed RAM. RAM may be changed at any

time. RAM 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

RAM size, its power consumption, and amount of time

the board is operating. Generally, a battery life from 5

to 10 years can be expected.

This chapter discusses changing RAM, saving and

retrieving variables, running 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 memory chip, you need to rem ove the

original chip, install the new one, and set jumper W4.

To install a new memory chip:

1. Turn off power to the RPC-52.

2. Remove the memory 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 goes 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 necessary, 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 with 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 through 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 replaced 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

procedure. The batter y may be replaced while pow er is

on. If you replace the batter y with power off, be sure to

reset the date and time. Also, data stored in RAM will

be lost.

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Remote-processing RPC-52 Manuel d'utilisateur Page 15

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