TS80C51RA2-VCA Atmel, TS80C51RA2-VCA Datasheet - Page 53

• Manufacturer Part Number: TS80C51RA2-VCA
• Description: IC MCU 8BIT 256BYTE 40MHZ 40-DIP
• Manufacturer: Atmel
• Series: 80Cr

Specifications of TS80C51RA2-VCA

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 40/30MHz
• Connectivity: UART/USART
• Peripherals: POR, PWM, WDT
• Number Of I /o: 32
• Program Memory Type: ROMless
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Oscillator Type: Internal
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 40-DIP (0.600", 15.24mm)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Program Memory Size: -
• Data Converters: -

9. TS87C51RB2/RC2/RD2 EPROM
9.1
9.2
9.2.1
9.2.2
4188F–8051–01/08
EPROM Structure
EPROM Lock System
Encryption Array
Program Lock Bits
The TS87C51RB2/RC2/RD2 EPROM is divided in two different arrays:
In addition a third non programmable array is implemented:
The program Lock system, when programmed, protects the on-chip program against software
piracy.
Within the EPROM array are 64 bytes of encryption array that are initially unprogrammed (all
FF’s). Every time a byte is addressed during program verify, 6 address lines are used to select a
byte of the encryption array. This byte is then exclusive-NOR’ed (XNOR) with the code byte, cre-
ating an encrypted verify byte. The algorithm, with the encryption array in the unprogrammed
state, will return the code in its original, unmodified form.
When using the encryption array, one important factor needs to be considered. If a byte has the
value FFh, verifying the byte will produce the encryption byte value. If a large block (>64 bytes)
of code is left unprogrammed, a verification routine will display the content of the encryption
array. For this reason all the unused code bytes should be programmed with random values.
This will ensure program protection.
The three lock bits, when programmed according to Table 9-1.9.2.3, will provide different level of
protection for the on-chip code and data.
Table 9-1.
U: unprogrammed,
P: programmed
• the code array:16/32/64 Kbytes.
• the encryption array:64 bytes.
• the signature array: 4 bytes.
Security
level
1
2
3
4
Program Lock bits
Program Lock Bits
LB1
U
P
U
U
LB2
U
U
P
U
LB3
U
U
U
P
Protection Description
No program lock features enabled. Code verify will still be
encrypted by the encryption array if programmed. MOVC
instruction executed from external program memory returns non
encrypted data.
MOVC instruction executed from external program memory are
disabled from fetching code bytes from internal memory, EA is
sampled and latched on reset, and further programming of the
EPROM is disabled.
Same as 2, also verify is disabled.
Same as 3, also external execution is disabled.
AT/TS8xC51Rx2
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