83C055 Philips Semiconductors, 83C055 Datasheet - Page 27

• Manufacturer Part Number: 83C055
• Description: Microcontrollers for TV and video MTV
• Manufacturer: Philips Semiconductors

Philips Semiconductors
14.2
Figures 10 and 11 show the timing diagrams for the
Program/Verify cycle. Programming operation:
1. RST should initially be held HIGH for at least
2. The RST pin may now be used as the serial data input
3. Next the address information for the location to be
4. The V
5. The next programming cycle may now be initiated by:
1996 Mar 22
Microcontrollers for TV and video (MTV)
2 machine cycles. P0.1 (PROG) and P0.0 (V
at V
these pins function as normal quasi-bidirectional I/O
ports and the programming equipment may pull these
lines LOW. However, prior to sending the 10-bit code
on the RST pin, the programming equipment should
drive these pins HIGH (V
for the data stream which places the 87C055 in the
Programming Mode. Data bits are sampled during the
clock HIGH time and thus should only change during
the time that the clock is LOW. Following transmission
of the last data bit, the RST pin should be held LOW.
programmed is placed on Port 2 and ASEL is used to
perform the address multiplexing, as previously
described (see Table 31; note 1).
a) At this time, Port 1 functions as an output.
b) A high voltage V
c) The data to be programmed into the EPROM array
placing the 87C055 in the Verify Mode; Port 3 is now
used as an output port. After four machine cycles
(48 clock periods), the contents of the addressed
location in the EPROM array will appear on Port 3.
a) Placing the address information at the inputs of the
b) Driving the V
c) Providing the byte to be programmed to Port 3 and
d) Bringing V
Programming operation
input (P0.0). This sets Port 1 as an input port.
is then placed on Port 3. This is followed by a
series of programming pulses applied to the PROG
pin (P0.1). These pulses are created by driving
P0.1 LOW and then HIGH. This pulse is repeated
until a total of 25 programming pulses have
occurred. At the conclusion of the last pulse, the
PROG signal should remain HIGH.
multiplexed buffers.
issuing the 26 programming pulses on the PROG
pin.
verifying the byte (see Table 33).
OH
PP
as a result of the RST operation. At this point,
signal may now be driven to the V
PP
PP
back down to the V
pin to the V
PP
level is then applied to the V
IH
).
PP
voltage level.
OH
level and
OH
PP
) will be
level,
PP
27
14.3
Erasure of the EPROM begins to occur when the chip is
exposed to light with wavelengths shorter than
approximately 4000 Angstroms. Since sunlight and
fluorescent lighting have wavelengths in this range,
exposure to these light sources over an extended time
(about 1 week in sunlight, or 3 years in room level
fluorescent lighting) could cause inadvertent erasure.
For this and secondary effects, it is recommended that an
opaque label be placed over the window. For elevated
temperature or environments where solvents are being
used, apply Kapton tape Fluorless (part number 2345-5) or
equivalent.
The recommended erasure procedure is exposure to
ultraviolet light (at 2537 Angstroms) to an integrated dose
of at least 15 Ws/cm
Exposing the EPROM to an ultraviolet lamp of
12000 W/cm
about 1 inch, should be sufficient. Erasure leaves the array
in an all logic 1s state.
14.4
The Signature Bytes are read by the same procedure as a
normal verify of locations 30H and 31H (the values are
shown in Table 32), except that the serial code indicated in
Table 33 for reading signature bytes should be used.
Table 32 Programming and Verification codes
Table 33 Implementing Program/Verify Modes
Note
1. Pulsed from V
Program user EPROM
Verify user EPROM
Read Signature Bytes
ADDRESS
30H
31H
OPERATION
Erasure Characteristics
Reading Signature Bytes
2
CONTENT
rating for 20 to 39 minutes, at a distance of
4BH
IH
15H
2
to V
.
IL
and returned to V
manufactured by Philips
87C055
SERIAL
CODE
83C145; 83C845
83C055; 87C055
286H
286H
280H
INDICATION
Product specification
(PROG)
P0.1
V
V
(1)
IH
IH
IH
.
(V
P0.0
V
V
V
PP
PP
IH
IH
)