RCA CDPl8S693 User Manual page 58

10. Using the PROM Programmer
The user should respond with either a "0" or a " 1".
The response to the prompt
LOWEST PROM ADDRESS (XX00)?
is used to generate the starting address on the file. For
example, the response "0100" causes data to be written
on the file as follows:
0100 XXXX XXXX XXXX XXXX XXXX XXXX XXXX XXXX;
0110 XXXX XXXX XXXX XXXX XXXX XXXX XXXX XXXX;
etc.
Be sure the correct starting address is assigned.
SAVE'd files on tape cassette will have a leader and
trailer of nulls appended automatically.
Example
Save RAM pages 08 through 12 (hex) under the file
on a tape in drive #1. The data is from a PROM with
starting address 0200.
MCDS PROM PROGRAMMER VER X
F, P, C, S, J,
V, U? S
# PAGES? A ..TEN PAGES WILL BE SAVED
TAPE#? 1
LOWEST PROM ADDRESS (XX00)? 0200
DONE
MCDS PROM PROGRAMMER VER X
F, V, P, C, S, J, U?
File Reader Subroutines
The File Reader Subroutine is a progam called by
either the PROGRAM or VERIFY routines. It loads
data from a file into the buffer RAM starting at page 8.
It is an intelligent loader that will search through a file
and load data in the address range of interest (+2
kilobytes from the initial address) ignoringextraneous
data. It will handle either hex or listing files created by
the COSMAC assemblers and files created by the
monitor program (W command). When the user
replies to the prompt
LOWEST PROM ADDRESS (XX00)?
the program takes that address as the first address in
the range and adds 2K to get the last address. It will
thus load up to 2 kilobytes of data, filling the basic
buffer (but not writing into any additional CDS RAM)
if there is sufficient data. Of course, if the file contains
less than 2 kilobytes in the address range, some of the
buffer will not be used. Once a 2-kilobyte file is loaded,
small PROM 's can be programmed from successive
pages of the buffer. Refer to the next section for an
example.
If no data is found, the program types
NO OBJECT CODE
In the tape cassette system, the program will restart
from the beginning.
Format errors detected on the cassette will cause the
program to type the following messages and restart
from the beginning.
FORMAT ERROR
LOAD ABORTED
When loading starts, the message
LOADING
is typed. At the completion of a successful load, the
word COMPLETED is added to the sentence. The
program then goes automatically into the program or
verify operation.
NOTE: In response to the prompt
LOWEST PROM ADDRESS (XX00)?
a full four-digit number followed by a carriage return
(CR) should be entered. If the user hits CR without
entering any numbers, the default address of 0000 is
used. Typing mistakes can be corrected by continuing
to type until the correct four digits have been entered
before hitting CR. Only the last four digits before the
CR are recognized and only the first two of the group
are meaningful—the last two are always taken as 00.
Below are some examples.
Response
0200(CR)
0251 (CR)
2(CR)
030244(CR)
03029(CR)
(CR)
Application Hints
It is good practice to verify that a PROM is erased
before attempting to program it. A suitable technique
is to use the "F " command to fill the buffer with 1 's or
0's and then the "V" command to verify the PROM
against it. When a PROM is being programmed to
work in an RCA 1800-series microprocessor-based
system, it is advisable to first fill the buffer with all 0's
before loading in the data to be programmed. This step
will set data in the unused addresses of the PROM to
00, which is an IDLE instruction in the RCA 1800-
series instruction set. Thus, an erratic program
fetching from an erroneous address will pick up the
idle instruction and stop. A PROM thus programmed
must use the same procedure when it is verified. That
is, the buffer is first filled with 0's, the data loaded, and
the verify operation is made. This technique assures
that no "errors" will appear when the programmed
"00" locations are verified against random data left in
the buffer.
An application note (ICAN-6847) describing a
hardware adjunct that can be used to program Intel
2732 PROM 's with this system is available on request.
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Yields
0200
0200
0000
0200
3000
0000