MC68020FE25E Freescale Semiconductor, MC68020FE25E Datasheet - Page 139

• Manufacturer Part Number: MC68020FE25E
• Description: IC MICROPROCESSOR 32BIT 132CQFP
• Manufacturer: Freescale Semiconductor

Specifications of MC68020FE25E

• Processor Type: M680x0 32-Bit
• Speed: 25MHz
• Voltage: 5V
• Mounting Type: Surface Mount
• Package / Case: 132-CQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -

level 6 interrupt is not processed. However, if the MC68020/EC020 is handling a level 7
interrupt (I2–I0 in the SR set to 111) and the external request is lowered to level 3 and
then raised back to level 7, a second level 7 interrupt is processed. The second level 7
interrupt is processed because the level 7 interrupt is transition sensitive. A level 7
interrupt is also generated by a level comparison if the request level and mask level are at
7 and the priority mask is then set to a lower level (with the MOVE to SR or RTE
instruction, for example). As shown in Figure 6-3 for level 6 interrupt request level and
mask level, this is the case for all interrupt levels.
Note that a mask value of 6 and a mask value of 7 both inhibit request levels of 1–6 from
being recognized. In addition, neither masks a transition to an interrupt request level of 7.
The only difference between mask values of 6 and 7 occurs when the interrupt request
level is 7 and the mask value is 7. If the mask value is lowered to 6, a second level 7
interrupt is recognized.
6-14
LEVEL 6 EXAMPLE
LEVEL 7 EXAMPLE
IF
IF
IF
IF STILL
IF
IF
IF
IF STILL
EXTERNAL IPL2–IPL0
001 ($6)
100 ($3)
001 ($6)
001 ($6)
100 ($3)
100 ($3)
000 ($7)
100 ($3)
000 ($7)
000 ($7)
Figure 6-3. Interrupt Recognition Examples
Freescale Semiconductor, Inc.
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THEN
AND STILL
AND STILL
AND RTE SO THAT
THEN
AND STILL
AND STILL
AND RTE SO THAT
INTERRUPT PRIORITY MASK (I2–I0 IN SR)
M68020 USER’S MANUAL
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101 ($5)
110 ($6)
110 ($6)
110 ($6)
101 ($5)
101 ($5)
111 ($7)
111 ($7)
111 ($7)
101 ($5)
INITIAL CONDITIONS
INITIAL CONDITIONS
THEN
THEN
AND
THEN
AND
THEN
THEN
THEN
LEVEL 6 INTERRUPT
NO ACTION
NO ACTION
LEVEL 6 INTERRUPT (LEVEL COMPARISON)
LEVEL 7 INTERRUPT
NO ACTION
NO ACTION
LEVEL 7 INTERRUPT (LEVEL COMPARISON)
ACTION
(LEVEL COMPARISON)
(TRANSITION)
(TRANSITION)
MOTOROLA