AT89C5131A-L Atmel Corporation, AT89C5131A-L Datasheet - Page 40

• Manufacturer Part Number: AT89C5131A-L
• Manufacturer: Atmel Corporation

Specifications of AT89C5131A-L

• Flash (kbytes): 32 Kbytes
• Max. Operating Frequency: 48 MHz
• Cpu: 8051-12C
• Max I/o Pins: 34
• Usb Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 1
• Twi (i2c): 1
• Uart: 1
• Sram (kbytes): 1.25
• Eeprom (bytes): 1024
• Self Program Memory: API
• Operating Voltage (vcc): 3.0 to 3.6
• Timers: 4
• Isp: UART/USB
• Watchdog: Yes

Flash Memory Status
Figure 21. Flash Memory Possible Contents
Memory Organization
40
0000h
AT89C5131A-L
7FFFh AT89C5131A-M
Default
Virgin
After ISP
Application
Table 41. Program Lock Bits of the SSB
Notes:
AT89C5131A-L parts are delivered with the ISP boot in the Flash memory. After ISP or
parallel programming, the possible contents of the Flash memory are summarized in
Figure 21:
In the AT89C5131A-L, the lowest 32K of the 64 Kbyte program memory address space
is filled by internal Flash.
When the EA is pin high, the processor fetches instructions from internal program Flash.
Bus expansion for accessing program memory from 32K upward is automatic since
external instruction fetches occur automatically when the program counter exceeds
7FFFh (32K). If the EA pin is tied low, all program memory fetches are from external
memory. If all storage is on chip, then byte location 7FFFh (32K) should be left vacant to
prevent and undesired pre-fetch from external program memory address 8000h (32K).
Security
Level
Program Lock Bits
1
2
3
1. U: unprogrammed or "one" level.
2. P: programmed or “zero” level.
3. WARNING: Security level 2 and 3 should only be programmed after Flash and code
verification.
LB0
U
P
P
Dedicated
ISP
After ISP
Application
Virgin
LB1
U
U
P
or
Protection Description
No program lock features enabled.
ISP programming of the Flash is disabled.
Same as 2, also verify through ISP programming interface is disabled.
After parallel
programming
Application
After parallel
programming
Dedicated
ISP
Application
Virgin
or
After parallel
programming
Application
Virgin
or
4338F–USB–08/07