AT80C51SND1C-ROTUL Atmel, AT80C51SND1C-ROTUL Datasheet - Page 26

• Manufacturer Part Number: AT80C51SND1C-ROTUL
• Description: IC MCU FLASH MP3 DECODER 80-TQFP
• Manufacturer: Atmel
• Series: 80Cr

Specifications of AT80C51SND1C-ROTUL

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 40MHz
• Connectivity: I²C, IDE/ATAPI, MMC, SPI, UART/USART, USB
• Peripherals: Audio, I²S, MP3, PCM, POR, WDT
• Number Of I /o: 44
• Program Memory Type: ROMless
• Ram Size: 2.25K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.3 V
• Data Converters: A/D 2x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 80-TQFP, 80-VQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Program Memory Size: -

7. Data Memory
Figure 1. Internal and External Data Memory Organization
7.1
7.1.1
26
Internal Space
AT8xC51SND1C
Lower 128 Bytes RAM
7FFh
00h
Internal ERAM
EXTRAM = 0
2K Bytes
The AT8xC51SND1C provides data memory access in 2 different spaces:
1. The internal space mapped in three separate segments:
2. The external space.
A fourth internal segment is available but dedicated to Special Function Registers, SFRs,
(addresses 80h to FFh) accessible by direct addressing mode. For information on this segment,
refer to the Section “Special Function Registers”, page 33.
Figure 1 shows the internal and external data memory spaces organization.
The lower 128 Bytes of RAM (see Figure 2) are accessible from address 00h to 7Fh using direct
or indirect addressing modes. The lowest 32 Bytes are grouped into 4 banks of 8 registers (R0
to R7). 2 bits RS0 and RS1 in PSW register (see Table 29) select which bank is in use according
to Table 26. This allows more efficient use of code space, since register instructions are shorter
than instructions that use direct addressing, and can be used for context switching in interrupt
service routines.
Table 26. Register Bank Selection
–
–
–
The lower 128 Bytes RAM segment
The upper 128 Bytes RAM segment
The expanded 2048 Bytes RAM segment
FFh
7Fh
80h
00h
Indirect Addressing
RS1
Direct or Indirect
0
0
1
1
Internal RAM
Internal RAM
Addressing
128 Bytes
128 Bytes
Upper
Lower
FFh
80h
RS0
0
1
0
1
Direct Addressing
Registers
Function
Special
Description
Register bank 0 from 00h to 07h
Register bank 1 from 08h to 0Fh
Register bank 2 from 10h to 17h
Register bank 3 from 18h to 1Fh
FFFFh
0800h
0000h
External XRAM
EXTRAM = 1
64K Bytes
4109L–8051–02/08