EVAL-ADUC842QSZ Analog Devices Inc, EVAL-ADUC842QSZ Datasheet - Page 20

• Manufacturer Part Number: EVAL-ADUC842QSZ
• Description: Analog MCU Evaluation Board
• Manufacturer: Analog Devices Inc
• Series: QuickStart™ Kitr
• Type: MCUr

Specifications of EVAL-ADUC842QSZ

• Silicon Manufacturer: Analog Devices
• Core Architecture: 8052
• Silicon Core Number: ADuC842
• Tool / Board Applications: General Purpose MCU, MPU, DSP, DSC
• Mcu Supported Families: ADUC8xx
• Contents: Evaluation Board, Power Supply, Cable, Software and Documentation
• Development Tool Type: Hardware - Eval/Demo Board
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: ADuC824
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

ADuC841/ADuC842/ADuC843
External Data Memory (External XRAM)
Just like a standard 8051 compatible core, the ADuC841/
ADuC842/ADuC843 can access external data memory by using
a MOVX instruction. The MOVX instruction automatically
outputs the various control strobes required to access the data
memory.
The parts, however, can access up to 16 MBytes of external data
memory. This is an enhancement of the 64 kBytes of external
data memory space available on a standard 8051 compatible core.
The external data memory is discussed in more detail in the
Hardware Design Considerations section.
Internal XRAM
The parts contain 2 kBytes of on-chip data memory. This
memory, although on-chip, is also accessed via the MOVX
instruction. The 2 kBytes of internal XRAM are mapped into
the bottom 2 kBytes of the external address space if the
CFG841/CFG842 bit is set. Otherwise, access to the external
data memory occurs just like a standard 8051. When using the
internal XRAM, Ports 0 and 2 are free to be used as general-
purpose I/O.
CFG841.7 = 0
CFG842.7 = 0
FFH
00H
Figure 24. Extended Stack Pointer Operation
ON-CHIP DATA
256 BYTES OF
(DATA +
STACK)
RAM
CFG841.7 = 1
CFG842.7 = 1
07FFH
100H
00H
ON-CHIP XRAM
(DATA + STACK
ON-CHIP XRAM
FOR EXSP = 1,
FOR EXSP = 0)
(DATA ONLY)
LOWER 256
UPPER 1792
DATA ONLY
BYTES OF
BYTES OF
Rev. 0 | Page 20 of 88
SPECIAL FUNCTION REGISTERS (SFRS)
The SFR space is mapped into the upper 128 bytes of internal
data memory space and is accessed by direct addressing only. It
provides an interface between the CPU and all on-chip periph-
erals. A block diagram showing the programming model of the
parts via the SFR area is shown in Figure 26.
All registers, except the program counter (PC) and the four
general-purpose register banks, reside in the SFR area. The SFR
registers include control, configuration, and data registers, which
provide an interface between the CPU and all on-chip peripherals.
FLASH/EE PROGRAM
REPROGRAMMABLE
ELECTRICALLY
COMPATIBLE
NONVOLATILE
2304 BYTES
FFFFFFH
000000H
62-kBYTE
MEMORY
CORE
RAM
8051
CFG841.0 = 0
CFG842.0 = 0
EXTERNAL
Figure 25. Internal and External XRAM
ADDRESS
MEMORY
SPACE)
SPACE
(24-BIT
DATA
Figure 26. Programming Model
FUNCTION
REGISTER
128-BYTE
SPECIAL
AREA
FFFFFFH
0007FFH
000800H
000000H
REPROGRAMMABLE
CFG841.0 = 1
CFG842.0 = 0
EXTERNAL
FLASH/EE DATA
OTHER ON-CHIP
2 × 12-BIT DACs
ADDRESS
ELECTRICALLY
TEMPERATURE
2 kBYTES
MEMORY
NONVOLATILE
PERIPHERALS
ON-CHIP
SPACE)
SPACE
(24-BIT
8-CHANNEL
XRAM
12-BIT ADC
DATA
SERIAL I/O
MEMORY
SENSOR
4-kBYTE
PWM
WDT
PSM
TIC