XE8000EV110 Semtech, XE8000EV110 Datasheet - Page 29

• Manufacturer Part Number: XE8000EV110
• Description: EVAL BOARD FOR XE8802AMI035LF
• Manufacturer: Semtech
• Type: MCUr

Specifications of XE8000EV110

• Contents: Fully Assembled Evaluation Board
• For Use With/related Products: XE88LC02MI035
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

4.1 Memory organisation
The XE8802 CPU is built with Harvard architecture. Harvard architecture uses separate instruction and data
memories. The instruction bus and data bus are also separated. The advantage of such a structure is that the CPU
can get a new instruction and read/write data simultaneously. The circuit configuration is shown in Figure 4-1. The
CPU has its 16 internal registers. The instruction memory has a capacity of 8192 22-bit instructions if the pin
NFASTREAD=1. The instruction memory has a capacity of 4096 22-bit instructions if the pin NFASTREAD=0. The
data memory space has 8 low power registers, the peripheral register space, 1024 bytes of RAM and the LCD
control register space.
µF µF
Figure 4-1. Memory mapping
The CPU internal registers are described in the CPU chapter. A short reference of the low power registers and
peripheral registers is given in 4.3.
4.2 Instruction memory and NFASTREAD
As indicated in chapter 4.1, the instruction memory can be organized in two ways: 4096 instructions with a speed
of 4 to 6 MIPS or 8192 instructions with a speed of 2 to 3 MIPS (see XE8802 performance chapter for more
details).
Important Note:
When programming the device, the correct NFASTREAD option has to be selected in the programmer.
Failure to do so may result in non-functional software. The default option in the programme is
NFASTREAD=1, i.e. the 8k instruction slower operation mode.
© Semtech 2006
0h1FFF
NFASTREAD=1
NFASTREAD=0
Instruction
8k x 22bit
4k x 22bit
capacity:
memory
XE8802 Sensing Machine Data Acquisition MCU
stat
i0h
i1h
i2h
i3h
iph
r0
r1
r2
r3
a
CPU
i0l
i1l
i2l
i3l
ipl
4-2
with ZoomingADC™ and LCD driver
0h8022
0h8000
0h047F
0h0080
0h007F
0h0008
0h0000
LCD registers
Low power
1024 bytes
Peripheral
capacity:
registers
RAM
RAM
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