MC68HC000EI20 Freescale Semiconductor, MC68HC000EI20 Datasheet - Page 117

• Manufacturer Part Number: MC68HC000EI20
• Description: IC MPU 16BIT 20MHZ 68-PLCC
• Manufacturer: Freescale Semiconductor

Specifications of MC68HC000EI20

• Processor Type: M680x0 32-Bit
• Speed: 20MHz
• Voltage: 3.3V, 5V
• Mounting Type: Surface Mount
• Package / Case: 68-PLCC
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -

SECTION 8
16-BIT INSTRUCTION
EXECUTION TIMES
This section contains listings of the instruction execution times in terms of external clock
(CLK) periods for the MC68000, MC68HC000, MC68HC001, and the MC68EC000 in 16-
bit mode. In this data, it is assumed that both memory read and write cycles consist of four
clock periods. A longer memory cycle causes the generation of wait states that must be
added to the total instruction times.
The number of bus read and write cycles for each instruction is also included with the
timing data. This data is shown as
where:
For example, a timing number shown as 18(3/1) means that the total number of clock
periods is 18. Of the 18 clock periods, 12 are used for the three read cycles (four periods
per cycle). Four additional clock periods are used for the single write cycle, for a total of 16
clock periods. The bus is idle for two clock periods during which the processor completes
the internal operations required for the instruction.
8.1 OPERAND EFFECTIVE ADDRESS CALCULATION TIMES
Table 8-1 lists the numbers of clock periods required to compute the effective addresses
for instructions. The total includes fetching any extension words, computing the address,
and fetching the memory operand. The total number of clock periods, the number of read
cycles, and the number of write cycles (zero for all effective address calculations) are
shown in the previously described format.
MOTOROLA
n is the total number of clock periods
r is the number of read cycles
w is the number of write cycles
The total number of clock periods (n) includes instruction fetch
and all applicable operand fetches and stores.
MC68000 8-/16-/32-MICROPROCESSORS USER’S MANUAL
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
NOTE
n(r/w)
8- 1