DS2790 Maxim Integrated Products, DS2790 Datasheet - Page 10

• Manufacturer Part Number: DS2790
• Description: Programmable 1-Cell Li-Ion Fuel Gauge and Protector
• Manufacturer: Maxim Integrated Products

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Memory Organization
The DS2790 incorporates several memory areas:
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The memory is implemented using the Harvard architecture, with separate address spaces for program and data
memory. A pseudo-Von Neumann memory map is also utilized placing ROM, application code, and data memory
into a single contiguous memory map. The pseudo-Von Neumann memory map allows data memory to be mapped
into program space, permitting code execution from data memory. In addition program memory may be mapped
into data space, permitting code constants to be accessed as data memory. Figure 4 shows the DS2790’s memory
map when executing from program memory space. See the MAXQ Family User's Guide: DS2790 Supplement for
memory map information when executing from data or ROM space.
The incorporation of EEPROM memory allows field upgrade of the firmware. EEPROM memory can be password
protected with a 16-word key, denying access to program memory by unauthorized individuals. ROM memory is
also available for high-volume, low-cost applications. Contact Dallas Semiconductor for more information on the
availability of ROM-based devices.
Figure 4. DS2790 Memory Map
4
Bh
Ch
Dh
Eh
Fh
8h
9h
0h
1h
2h
4k words of utility ROM contain a debugger, program loader, and SHA-1 routines
4k words of EEPROM memory for application program storage
256 words of SRAM for storage of temporary variables
64 words of EEPROM memory for data storage
8 words of ADC conversion data information
16-level stack memory for storage of program return addresses and general-purpose use
00h
00h
PERIPHERAL
REGISTERS
REGISTERS
SYSTEM
16 × 16
STACK
DPC
PFX
AP
SP
DP
M0
M1
M2
IP
A
0Fh
1Fh
FFFFh
8FFFh
0FFFh
8000h
0000h
MEMORY SPACE
USER PROGRAM
UTILITY ROM
PROGRAM
MEMORY
4K × 16
4K × 16
DS2790 Programmable 1-Cell Li-Ion Fuel Gauge and Protector
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9FFFh
FFFFh
8000h
027Fh
01FFh
0200h
0000h
DATA MEMORY
EEPROM DATA
(BYTE MODE)
UTILITY ROM
SRAM DATA
4K × 16
128 × 8
512 × 8
8FFFh
FFFFh
8000h
600Ah
013Fh
00FFh
6003h
0100h
0000h
DATA MEMORY
EEPROM DATA
(WORD MODE)
UTILITY ROM
SRAM DATA
ADC DATA
256 × 16
4K × 16
64 × 16
8 × 16