DS80C323 Maxim, DS80C323 Datasheet - Page 11

• Manufacturer Part Number: DS80C323
• Description: The DS80C320/DS80C323 are fast 80C31/80C32-compatible microcontrollers
• Manufacturer: Maxim

Table 1 shows the speed for each class of instruction. Note that many of the instructions have multiple op
codes. There are 255 op codes for 111 instructions. Of the 255 op codes, 159 are three times faster than
the original 80C32. While a system that emphasizes those instructions will see the most improvement, the
large total number that receive a 3 to 1 improvement assure a dramatic speed increase for any system. The
speed improvement summary is provided below.
SPEED ADVANTAGE SUMMARY
MEMORY ACCESS
The DS80C320/DS80C323 do not contain on-chip ROM and 256 bytes of scratchpad RAM. Off-chip
memory is accessed using the multiplexed address/data bus on P0 and the MSB address on P2. Figure 3
shows a typical memory connection. Timing diagrams are provided in the Electrical Specifications
section. Program memory (ROM) is accessed at a fixed rate determined by the crystal frequency and the
actual instructions. As previously mentioned, an instruction cycle requires 4 clocks. Data memory (RAM)
is accessed according to a variable-speed MOVX instruction as described below.
Figure 3. Typical Memory Connection
#OP CODES
255
159
51
43
2
IMPROVEMENT
Average: 2.5
SPEED
3.0 x
1.5 x
2.0 x
2.4 x
DS80C320/DS80C323 High-Speed/Low-Power Microcontrollers
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