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10. Using the PROM Programmer
The PROM Program mer is a hardware and
software package that facilitates user programming of
RCA and other industry-standard PROM ’s. Specific
ally, the RCA CDPl8U42, the Intel 2708, 2758, and
2716 UV-erasable PROM ’s, or equivalent PROM ’s
can be programmed with this system. In addition, Intel
l702-type PROM ’s can be read (but notprogrammed)
and copied into lower-power CDPl8U42 CMOS
PROM ’s or combined into larger-size PROM ’s. The
PROM Program mer is included with the CDP-
l8S694Vl and V3 systems and may be added to the
CDPl8S693Vl and V3 systems by means of the
PROM Programmer package CDPl8S680.
The PROM Programmer package includes a plug-in
Microboard module and a magnetic tape cassette
containing the operating software. The software is
designed for flexibility so that, in addition to the
numerous basic operations provided, more sophisti
cated procedures can be derived from these building
blocks. For example, a PROM can be copied from
another PROM or programmed from a tape-resident
file. The user can also combine two smaller PROM ’s
into a larger one (two 2708’s copied into one 27l6).
PROM ’s are automatically verified after program
ming. The user, however, can manually verify the
erasure of a PROM , verify one PROM against
another, or verify a PROM against a tape-resident file.
These operations can be done with either positive
(non-inverted) or negative (inverted) data.
An additional feature allows PROM ’s to be saved
on a tape file (in a reloadable format) that can be used
to generate masked ROM’s. For PROM production
purposes, a softw are feature facilitates rapid
programming of many PROM ’s from the same source.
Installation
The PROM Programmer Module, as provided with
the CDPl8S694Vl and V3, is installed in the bottom
slot of the chassis. When the module is to be used for
programming PROM ’s, the user should remove the
top cover and exchange the PROM Programmer
module for the Microboard module in the top slot. By
having the PROM programmer module in the top slot,
access is provided to the three PROM programming
sockets.
An external power supply is required as a
programming voltage to be connected to jack J3,
labelled PROG PWR. The voltage required for each
PROM is given in the PROM manufacturer’s data
specification sheet. The supply must be well regulated
and capable of supplying peak currents 'of 100
milliamperes. A -9-volt supply connected to J2 is also
necessary when the programmer is used with a 1702
PROM. J 1 is a ground connection. In addition to the
external power supplies (Programming Power and -9
volts), voltages of +12 volts and -5 volts (both ±5%)
must be supplied to the M icroboard Universal
Backplane pins 20 and 11, respectively, when 1702 or
2708 devices are to be operated on. D etailed
specifications for the power supply requirements are
given in Appendix I.
The PROM programmer module is assigned to
Group Select 4. The module generates a signal on flag
line EF1 of the CPU indicatingwhetherthe 1702/1842
switch is in the correct position.
Memory Organization and Use
The memory map for the PROM Programmer
software is given in Fig. 17. The program loads starting
at address 0000 and occupies the lowest two kilobytes
of RAM. The hexadecimal addresses from 0800 to
0FFF comprise a data buffer area used to hold data
moved to and from the PROM being operated on. The
buffer memory is treated in pages, where a page is
defined as 256 bytes. Thus, the first page of buffer
memory occupies the hexadecimal addresses 0800
through 08FF and is called page 8; the second page,
0900 through 09FF, is called page 9; etc. The data of a
1702 or CDP18U42 occupy one page, a 2708 or 2758
four pages, and a 2716 eight pages.
The program asks for the starting page m the data
buffer against which operations are to be performed.
