39
7
6
5
4
3
2
1
0
Bit positions
0
0
0
0
0
0
1
0
Bit
0 No A/D self calibration
1 A/N appended to response
2 <cr> <lf> if appended after ACK/NAK
3 no echo
4 DXD Command set
5 Error Status Character on
7 no noise test
7
6
5
4
3
2
1
0
Bit positions
0
0
0
0
0
1
1
0
Bit
0 No A/D self- calibration
1 A/N appended to response
2 <cr> only
3 no echo
4 DXD Command set
5 Error Status Character on
7 no noise test
ENTERING the MODE BYTE setting into the DXD EEProm
address location “001”:
The DXD EEProm locations, by design, are defined to contain
numbers from 000 to 255. Setting the appropriate bit or bits
in the MODE byte (address location “001”), therefore neces-
sitates a conversion from the bit settings described above.
Each one of the 8 bit locations (7 – 0) in the mode byte con-
trols a function based on whether or not the bit is a ‘1’ or ‘0’.
Each bit location represents a “binary weighting” , or decimal
value dictated by its position in the byte. A ‘1’ in the position
carries the full numeric value; a ‘o’ carries the value of 0. The
weighting is as follows:
76543210 bit position numeric value
00000001 = 1
00000010 = 2
00000100 = 4
00001000 = 8
00010000 = 16
00100000 = 22
01000000 = 64
10000000 = 128
Example 1 If you want to set the “Error status character”
to “A/N”, bit position 1 is set to a ‘1’. This has
a numeric value of 2 (according to its position
in the byte), so a “002” is written into address
location “001”.
Example 2 If you want to turn the error status character off
altogether, bit 5 must be set to a ‘1’, which has
a numeric value of 32, therefore “032” is written
into address location “001”.
Example 3 If you wish to have both “A/N” appended (bit 1),
and the <cr> without the <lf> (bit 2), both bit
2 and bit 3 must be set to ‘1’, their respective
numeric values are added together (2+4=6) and
“006” is written into address location “001”.
Note that if all of the bits are set to ‘1’ (actually
an undefined state), the values of all of the bits
added together equal 255. If no bits are set, then
the total value equals 000.
To write information into EEProm address location “001”
it is necessary to use the “ER” and “ew” library commands
defined earlier in this document. Please be aware that when