MC68340AG16VE Freescale Semiconductor, MC68340AG16VE Datasheet - Page 233

• Manufacturer Part Number: MC68340AG16VE
• Description: IC MPU 32BIT 16MHZ 144-LQFP
• Manufacturer: Freescale Semiconductor

Specifications of MC68340AG16VE

• Processor Type: M683xx 32-Bit
• Speed: 16MHz
• Voltage: 3.3V
• Mounting Type: Surface Mount
• Package / Case: 144-LQFP
• Controller Family/series: 68K
• Core Size: 32 Bit
• No. Of I/o's: 16
• Cpu Speed: 16MHz
• No. Of Timers: 2
• Embedded Interface Type: UART
• Digital Ic Case Style: LQFP
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -

5.7.2.3 TIMING EXAMPLE 3—NEGATIVE TAILS. This example (see Figure 5-36) shows
how to use negative tail figures for branches and other change-of-flow instructions. In this
example, bus speed is assumed to be four clocks per access. Instruction three is at the
branch destination.
Although the CPU32 has a two-word instruction pipeline, internal delay causes minimum
branch instruction time to be three bus cycles. The negative tail is a reminder that an extra
two clocks are available for prefetching a third word on a fast bus; on a slower bus, there
is no extra time for the third word.
5-96
CONTROLLER
INSTRUCTION
CONTROLLER
EXECUTION
CLOCK
TIME
BUS
CONTROLLER
INSTRUCTION
CONTROLLER
EXECUTION
1
CLOCK
TIME
BRANCH OFFSET
BUS
MOVEQ #7,D1
2
1
MOVEQ
MOVEQ
1 PRE-
FETCH
3
#7,D1
Figure 5-36. Example 3—Branch Negative Tail
MOVEQ
Figure 5-35. Example 2—Branch Not Taken
2
4
Freescale Semiconductor, Inc.
3
For More Information On This Product,
2 PRE-
FETCH
D1,D0
5
CMP
CMP
4
MOVEQ
BRA.W
MOVE.L
6
OFFSET
MC68340 USER’S MANUAL
CALC
Go to: www.freescale.com
5
OFFSET
CALC
7
BLE.B NOT TAKEN
Instructions
6
8
TAKEN
7
FETCH MOVE.L
BRA.W FARAWAY
3 PRE-
FETCH
TAKEN
9
NOT
8
0
9
MOVE TO
#7, D1
FARAWAY
D1, D0
4 PRE-
FETCH
1
(A0)
0
2
MOVE.L D1,(AO)
1
INSTRUCTION
WRITE
FETCH NEXT
3
FOR 4
2
4
TAKEN
3
WRITE
FOR 4
5
4
6
MOVE.L D1,D0
7
PREFETCH
MOTOROLA
8
MOVE
TO D0
9