COP8SG National Semiconductor, COP8SG Datasheet - Page 16

• Manufacturer Part Number: COP8SG
• Description: 8-Bit CMOS ROM Based and OTP Microcontrollers with 8k to 32k Memory/ Two Comparators and USART
• Manufacturer: National Semiconductor

www.national.com
5.0 Functional Description
Memory address ranges 0200 to 027F and 0300 to 037F are
unavailable on the COP8SGx5 and, if read, will return under-
fined data.
5.5 ECON (CONFIGURATION) REGISTER
For compatibility with COP8SGx7 devices, mask options are
defined by an ECON Configuration Register which is pro-
grammed at the same time as the program code. Therefore,
the register is programmed at the same time as the program
memory.
The format of the ECON register is as follows:
Bit 7
Bit 6
Bit 5
Bits 4, 3 = 0, 0 External CKI option selected. G7 is avail-
Bit 2
Bit 1
Bit 0
5.6 USER STORAGE SPACE IN EPROM
The ECON register is outside of the normal address range of
the ROM and can not be accessed by the executing soft-
ware.
The COP8 assembler defines a special ROM section type,
CONF, into which the ECON may be coded. Both ECON and
User Data are programmed automatically by programmers
that are certified by National.
The following examples illustrate the declaration of ECON
and the User information.
Bit 7
X
= x
= 1
= 0
= 1
= 1
= 0
= 1
= 0
= 1
= 0
Bit 6
POR
= 0, 1 R/C oscillator option selected. G7 is avail-
= 1, 0 Crystal oscillator with on-chip crystal bias
= 1, 1 Crystal oscillator with on-chip crystal bias
SECURITY
Bit 5
This is for factory test. The polarity is “Don’t
Care.”
Power-on reset enabled.
Power-on reset disabled.
Security enabled.
able as a HALT restart and/or general pur-
pose input. CKI is clock input.
able as a HALT restart and/or general pur-
pose input. CKI clock input. Internal R/C
components are supplied for maximum R/C
frequency.
resistor disabled. G7 (CKO) is the clock
generator output to crystal/resonator.
resistor enabled. G7 (CKO) is the clock
generator output to crystal/resonator.
WATCHDOG feature disabled. G1 is a gen-
eral purpose I/O.
WATCHDOG feature enabled. G1 pin is
WATCHDOG output with weak pullup.
Force port I compatibility. Disable port F
outputs and pull-ups. This is intended for
compatibility with existing code and Mask
ROMMed devices only. This bit should be
programmed to 0 for all other applications.
Enable full port F capability.
HALT mode disabled.
HALT mode enabled.
CKI 2
Bit 4
CKI 1
Bit 3
WATCH
Bit 2
DOG
(Continued)
F-Port
Bit 1
HALT
Bit 0
16
intensity X exposure time) for erasure should be a minimum
of 15W-sec/cm
Syntax:
[label:] .sect
Example: The following sets a value in the ECON register
and User Identification for a COP8SGR728M7. The ECON
bit values shown select options: Power-on enabled, Security
disabled, Crystal oscillator with on-chip bias disabled,
WATCHDOG enabled and HALT mode enabled.
5.7 OTP SECURITY
The device has a security feature that, when enabled, pre-
vents external reading of the OTP program memory. The se-
curity bit in the ECON register determines, whether security
is enabled or disabled. If the security feature is disabled, the
contents of the internal EPROM may be read.
If the security feature is enabled, then any attempt to ex-
ternally read the contents of the EPROM will result in the
value FF Hex being read from all program locations Un-
der no circumstances can a secured part be read. In ad-
dition, with the security feature enabled, the write operation
to the EPROM program memory and ECON register is inhib-
ited. The ECON register is readable regardless of the state
of the security bit. The security bit, when set, cannot be
erased, even in windowed packages. If the security bit is
set in a device in a windowed package, that device may be
erased but will not be further programmable.
If security is being used, it is recommended that all other bits
in the ECON register be programmed first. Then the security
bit can be programmed.
5.8 ERASURE CHARACTERISTICS
The erasure characteristics of the device are such that era-
sure begins to occur when exposed to light with wavelengths
shorter than approximately 4000 Angstroms (A r ). It should be
noted that sunlight and certain types of fluorescent lamps
have wavelengths in the 3000A r - 4000A r range.
After programming, opaque labels should be placed over the
window of windowed devices to prevent unintentional era-
sure. Covering the window will also prevent temporary func-
tional failure due to the generation of photo currents.
The recommended erasure procedure for windowed devices
is exposure to short wave ultraviolet light which has a wave-
length of 2537 Angstroms (A r ). The integrated dose (i.e. UV
5.9 RESET
The devices are initialized when the RESET pin is pulled low
or the On-chip Power-On Reset is enabled.
.sect
.db
.db
.endsect
econ, conf
0x55
'my v1.00' ;user data declaration
.db
.db
.endsect
2
.
econ, conf
value
<user information>
;por, xtal, wd, halt
; up to 8 bytes
;1 byte,
;configures options