AT83C5134 Atmel Corporation, AT83C5134 Datasheet - Page 25

• Manufacturer Part Number: AT83C5134
• Manufacturer: Atmel Corporation

Specifications of AT83C5134

• Max. Operating Frequency: 32 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): 512
• Operating Voltage (vcc): 2.7 to 3.6
• Timers: 4
• Mask Rom (kbytes): 8
• Watchdog: Yes

8. Program/Code Memory
8.1
8.1.1
7683C–USB–11/07
External Code Memory Access
Memory Interface
The AT83C5134/35/36 implement 16 or 32 Kbytes of on-chip program/code memory. Figure 8-1
shows the split of internal and external program/code memory spaces depending on the
product.
Figure 8-1.
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 8-2 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 8-1 describes the exter-
nal memory interface signals.
Figure 8-2.
If the program executes exclusively from on-chip code memory (not from external memory),
beware of executing code from the upper byte of on-chip memory 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.
Program/Code Memory Organization
External Code Memory Interface Structure
FFFFh
3FFFh
4000h
0000h
AT89C5131
PSEN
ALE
External Code
P2
P0
AT83C5135
48 Kbytes
16 Kbytes
ROM
AD7:0
A15:8
Latch
FFFFh
7FFFh
8000h
0000h
A7:0
External Code
AT83C5136
32 Kbytes
32 Kbytes
A15:8
A7:0
D7:0
OE
ROM
EPROM
Flash
AT83C5134/35/36
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