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ML51/ML54/ML56
Sep. 01, 2020
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Manual
If desired, user may enable the automatic address recognition feature in Mode 1. In this configuration,
the stop bit takes the place of the ninth data bit. RI is set only when the received command frame
address matches the device’s address and is terminated by a valid stop bit.
Using the automatic address recognition feature allows a master to selectively communicate with one
or more slaves by invoking the
“Given” slave address or addresses. All of the slaves may be contacted
by using the “Broadcast” address. Two SFR are used to define the slave address, SADDR, and the
slave address mask, SADEN. SADEN is used to define which bits in the SADDR are to be used and
which bits are “don’t care”. The SADEN mask can be logically ANDed with the SADDR to create the
“Given” address, which the master will use for addressing each of the slaves. Use of the “Given”
address allows multiple slaves to be recognized while excluding others.
The following examples will help to show the versatility of this scheme.
Example 1, slave 0:
SADDR = 11000000b
SADEN = 11111101b
Given = 110000X0b
Example 2, slave 1:
SADDR = 11000000b
SADEN = 11111110b
Given = 1100000Xb
In the above example SADDR is the same and the SADEN data is used to differentiate between the
two slaves. Slave 0 requires 0 in bit 0 and it ignores bit 1. Slave 1 requires 0 in bit 1 and bit 0 is
ignored. A unique address for Slave 0 would be 1100 0010 since slave 1 requires 0 in bit 1. A unique
address for slave 1 would be 11000001b since 1 in bit 0 will exclude slave 0. Both slaves can be
selected at the same time by an address, which has bit 0 = 0 (for slave 0) and bit 1 = 0 (for slave 1).
Thus, both could be addressed wi
th 11000000b as their “Broadcast” address.
In a more complex system the following could be used to select slaves 1 and 2 while excluding slave
0:
Example 1, slave 0:
SADDR = 11000000b
SADEN = 11111001b
Given = 11000XX0b
Example 2, slave 1:
SADDR = 11100000b
SADEN = 11111010b
Given = 11100X0Xb