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MOTOROLA
MC68306 USER'S MANUAL
7-9
1
MUX
1
G1
1
MUX
1
G1
OUTPUT
FROM
SYSTEM
LOGIC
FROM
PREVIOUS
CELL
1D
C1
CLOCK DR
1D
C1
UPDATE DR
TO NEXT
CELL
TO OUTPUT
DRIVER
1 – EXTEST
0 – OTHERWISE
SHIFT DR
FROM PIN
INPUT TO
SYSTEM
LOGIC
Figure 7-7. Bidirectional Cell (IOx0.Cell)
IO.CELL
EN
FROM LAST CELL
OUTPUT
DATA
INPUT
DATA
OUTPUT
ENABLE
I/O
PIN
TO NEXT CELL
*
NOTE: More than one lO.Cell could be serially connected and controlled by a single En.Cell.
EN.CELL
Figure 7-8. General Arrangement for Bidirectional Pins
7.4 INSTRUCTION REGISTER
The MC68306 IEEE 1149.1 implementation includes the three mandatory public
instructions (EXTEST, SAMPLE/PRELOAD, and BYPASS), the optional public ID
instruction, plus one additional public instruction (CLAMP) defined by IEEE 1149.1. The