4
M68000 USER’S MANUAL ADDENDUM
MOTOROLA
2.0 SIGNAL DESCRIPTION
Change Figure 3-3 on Page 3-2.
Figure 1. Input and Output Signals (MC68EC000 and MC68SEC000)
2.1 Data Bus (D15-D0)
In Section 3.2 on page 3-4, replace “The MC68EC000 and MC68HC001 use D7-D0 in 8-bit mode, and D15-
D8 are undefined.” with “Using the MC68HC001, MC68EC000, and MC68SEC000 mode pin, you can
statically select either 8- or 16-bit modes for data transfer. The MC68EC000, MC68SEC000, and
MC68HC001 use D7-D0 in 8-bit mode. D15-D8 are undefined.”
2.2 Bus Arbitration Control
In Section 3.4 on page 3-5, the sentence “In the 48-pin version of the MC68008 and MC68EC000, no pin is
available for the bus grant acknowledge signal; this microprocessor uses a two-wire bus arbitration
scheme.” should read “In the 64-pin MC68EC000 and MC68SEC000, no pin is available for the bus grant
acknowledge signal. These microprocessors use a two-wire bus arbitration scheme.”
2.3 System Control
The Mode subsection heading of Section 3.6 on page 3-7 should read ‘‘Mode (MODE) (MC68HC001/
68EC000/68SEC000).’’
2.4 MC68SEC000 Low-Power Mode
Add the following to Sections 4 and 5, Bus Operation.
The MC68SEC000 has been redesigned to provide fully static- and low-power operation. This section
describes the recommended method for placing the MC68SEC000 into a low-power mode to reduce the
ADDRESS BUS
DATA BUS
ASYNCHRONOUS
BUS CONTROL
BUS ARBITRATION
CONTROL
INTERRUPT
CONTROL
PROCESSOR
STATUS
A23-A0
D15-D0
AS
R/W
UDS
LDS
DTACK
BERR
RESET
HALT
MODE
SYSTEM
CONTROL
V
CC
GND
CLK
MC68SEC000
FC0
FC1
FC2
IPL0
IPL1
IPL2
AVEC
BR
BG
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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