AT89C5131A-L Atmel Corporation, AT89C5131A-L Datasheet - Page 47

• 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

On-chip Expanded
RAM (ERAM)
Figure 25. Internal and External Data Memory Address
4338F–USB–08/07
0FFh or 3FFh(*)
00
ERAM
The AT89C5131A-L provides additional Bytes of random access memory (RAM) space
for increased data parameters handling and high level language usage.
AT89C5131A-L devices have an expanded RAM in the external data space; maximum
size and location are described in Table 44.
Table 44. Description of Expanded RAM
The AT89C5131A-L has on-chip data memory which is mapped into the following four
separate segments.
1. The Lower 128 bytes of RAM (addresses 00h to 7Fh) are directly and indirectly
2. The Upper 128 bytes of RAM (addresses 80h to FFh) are indirectly addressable
3. The Special Function Registers, SFRs, (addresses 80h to FFh) are directly
4. The expanded RAM bytes are indirectly accessed by MOVX instructions, and
The lower 128 bytes can be accessed by either direct or indirect addressing. The Upper
128 bytes can be accessed by indirect addressing only. The Upper 128 bytes occupy
the same address space as the SFR. That means they have the same address, but are
physically separate from SFR space.
AT89C5131A-L
Part Number
addressable.
only.
addressable only.
with the EXTRAM bit cleared in the AUXR register (see Table 44)
0FFh
80h
7Fh
00
indirect accesses
direct or indirect
128 bytes
128 bytes
accesses
Internal
Internal
Upper
Lower
RAM
RAM
ERAM Size
1024
0FFh
80h
direct accesses
Function
Register
Special
00FFh up to 03FFh (*)
(*) Depends on XRS1..0
Start
00h
0FFFFh
0000
Address
External
Memory
Data
End
3FFh
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