AT89C5131A-L Atmel Corporation, AT89C5131A-L Datasheet - Page 27

• 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

Program/Code
Memory
External Code Memory
Access
Memory Interface
4338F–USB–08/07
The AT89C5131A-L implement 32 Kbytes of on-chip program/code memory. Figure 13
shows the split of internal and external program/code memory spaces depending on the
product.
The Flash memory increases EPROM and ROM functionality by in-circuit electrical era-
sure and programming. Thanks to the internal charge pump, the high voltage needed for
programming or erasing Flash cells is generated on-chip using the standard V
age. Thus, the Flash Memory can be programmed using only one voltage and allows In-
application Software Programming commonly known as IAP. Hardware programming
mode is also available using specific programming tool.
Figure 13. Program/Code Memory Organization
Note:
The external memory interface comprises the external bus (Port 0 and Port 2) as well as
the bus control signals (PSEN, and ALE).
Figure 14 shows the structure of the external address bus. P0 carries address A7:0
while P2 carries address A15:8. Data D7:0 is multiplexed with A7:0 on P0. Table 33
describes the external memory interface signals.
Figure 14. External Code Memory Interface Structure
If the program executes exclusively from on-chip code memory (not from external mem-
ory), beware of executing code from the upper byte of on-chip memory (7FFFh) and
thereby disrupting I/O Ports 0 and 2 due to external prefetch. Fetching code constant
from this location does not affect Ports 0 and 2.
AT89C5131
PSEN
ALE
P2
P0
FFFFh
7FFFh
8000h
0000h
AD7:0
A15:8
AT89C5131A-L
External Code
Latch
32 Kbytes
32 Kbytes
Flash
A7:0
A15:8
A7:0
D7:0
OE
EPROM
Flash
DD
volt-
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