Texas Instruments 990 Operation Manual page 170

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945255-9701
The first example defines the ROM/PROM characteristics as follows:
Loop level
Bit increment
Maximum iteration count
Bit displacement
=
I
=4
=
100
16
=
256
10
=
0 (default)
The second example defines the ROM/PROM characteristics as follows:
Loop level
=
3
Bit increment
=
I
Maximum iteration count
=
4
Bit displacement
=
3
7.5.3.8 Define PROM/ROM Characteristics (RC). The Define PROM/ROM Characteristics sub-
command defines the physical hardware characteristics needed to transfer data to the
PROM/ROM.
Syntax definition:
PP
{t,' ... }
RC {h' ... } <width> {h' ... } <high or low> {h' ... } <pwl> [{h' ... }
[<retries>] [{h' ... } [<duty CYcle>] [ {h' ... } <pgmable bitS>]]]
Parameters:
width Number of bits per word in the PROM/ROM physical
organization. Required parameter. Hexadecimal
number.
high or low Value that specifies whether high or low
logic level output conditions are to be
programmed. The value is 0 if low and is
1 if high. Required parameter.
pwl Normal pulse width to be used for programming. The
pulse width is entered as an index value between 1
and 6 obtained from a table in Appendix G. Required
parameter.
retries Number of times programming is to be retried using
the normal pulse width if a programming failure
occurs. Hexadecimal number.
Duty cycle Duty cycle to be maintained while programming a
PROM. Hexadecimal number. The value is the
percentage of the total time (programming time
plus delay time) that the programming pulse is
on. The normal duty cycle varies between 16%
and 50%. For example, a value of 20
16
is a
duty cycle of 32%.
pgmable bits Number of bits that can be physically programmed
simultaneously.
7-20
Digital Systems Division .