TS87C58X2-LCB Atmel, TS87C58X2-LCB Datasheet - Page 37

• Manufacturer Part Number: TS87C58X2-LCB
• Description: IC MCU 8BIT 32K OTP 30MHZ 44PLCC
• Manufacturer: Atmel
• Series: 87Cr

Specifications of TS87C58X2-LCB

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 30/20MHz
• Connectivity: UART/USART
• Peripherals: POR, WDT
• Number Of I /o: 32
• Program Memory Size: 32KB (32K x 8)
• Program Memory Type: OTP
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Oscillator Type: Internal
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 44-PLCC
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Data Converters: -

17. TS87C54/58X2 EPROM
17.1
17.2
17.2.1
17.2.2
4431E–8051–04/06
EPROM Structure
EPROM Lock System
Encryption Array
Program Lock Bits
The TS87C54/58X2 EPROM is divided in two different arrays:
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 17-1., will provide different level of
protection for the on-chip code and data.
Table 17-1.
U: unprogrammed,
P: programmed
WARNING: Security level 2 and 3 should only be programmed after EPROM and Core
verification.
• the code array:16/32 Kbytes.
• the encryption array:64 bytes.
• In addition a third non programmable array is implemented:
• the signature array: 4 bytes.
Security
level
1
2
3
4
Program Lock Bits
Program Lock bits
LB1
U
U
U
P
LB2
U
U
U
P
LB3
U
U
U
P
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.
Protection Description
AT/TS8xC54/8X2
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