T89C5115-TISIM Atmel, T89C5115-TISIM Datasheet - Page 24

• Manufacturer Part Number: T89C5115-TISIM
• Description: IC 8051 MCU FLASH 16K 28SOIC
• Manufacturer: Atmel
• Series: 89Cr

Specifications of T89C5115-TISIM

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 40MHz
• Connectivity: UART/USART
• Peripherals: POR, PWM, WDT
• Number Of I /o: 20
• Program Memory Size: 16KB (16K x 8)
• Program Memory Type: FLASH
• Eeprom Size: 2K x 8
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 3 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-SOIC (7.5mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Data Memory
Internal Space
Lower 128 Bytes RAM
24
AT89C5115
The T89C5115 provides data memory access in two different spaces:
The internal space mapped in three separate segments:
•
•
•
A fourth internal segment is available but dedicated to Special Function Registers,
SFRs, (addresses 80h to FFh) accessible by direct addressing mode.
Figure 9 shows the internal data memory spaces organization.
Figure 9. Internal memory - RAM
The lower 128 Bytes of RAM (See Figure 10) 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). Two bits RS0 and RS1 in PSW register (See Table 17)
select which bank is in use according to Table 16. This allows more efficient use of code
space, since register instructions are shorter than instructions that use direct address-
ing, and can be used for context switching in interrupt service routines.
Table 16. Register Bank Selection
The next 16 Bytes above the register banks form a block of bit-addressable memory
space. The C51 instruction set includes a wide selection of singlebit instructions, and
the 128 bits in this area can be directly addressed by these instructions. The bit
addresses in this area are 00h to 7Fh.
The lower 128 Bytes RAM segment.
The upper 128 Bytes RAM segment.
The expanded 256 Bytes RAM segment (XRAM).
RS1
0
0
1
1
FFh
00h
Internal XRAM
256 Bytes
RS0
0
1
0
1
FFh
7Fh
80h
00h
Description
Register bank 0 from 00h to 07h
Register bank 0 from 08h to 0Fh
Register bank 0 from 10h to 17h
Register bank 0 from 18h to 1Fh
Indirect Addressing
Direct or Indirect
Internal RAM
Internal RAM
Addressing
128 Bytes
128 Bytes
Upper
Lower
FFh
80h
Direct Addressing
Registers
Function
Special
4128G–8051–02/08