Yaesu FT-757GX Technical Supplement page 13

As illustrated in the Frequency Enter Command
example, frequency parameter data is sent least­
significant digit first. The Frequency Step Com­
mand example shows how dummy data
required in all other commands, preceding the
instruction byte.
Once the 5-byte command has been sent to the
transceiver, it will respond with the appropriate
change indicated on the front panel display. If
not, an error has occurred either in the data sent
or in the interface connection, so these should
PROGRAMMING
Data output routines in the external computer
may have to be in machine language, as· BASIC
and other high-level languages are generally too
("f/J(/J")
START
COMMAND BYTE CODES
DATA
No.
COMMAND
I 2 3 4
I
SPLIT x x x x
MR/VFO
2 x x x x
V.,. M
3 x x
x x
4 D LOCK
x x x x
VFO A/B
5 x x x x
M.,. V
6
x x x x
500
7 UP x x x x
8 500 OWN
x x x x
CLAR
9 x x x x
10
f � j,
Frequency set
II V�M
x x x x
"X"
=
dummy data (value irrelevant)
J) J) J) @
:
Frequency data, LSB first.
12.345.67
Example:
(referring to the data locations in the Table):
(i) - 67
@
@ -23
® -01
be inspected bef o re the command is sent to the
transceiver again. Note that the controls on the
transceiver are not disabled when exerc1smg
is
external control; touching any control on the
transceiver that duplicates an externally-controlled
function will invalidate function indications on the
computer display. The external control program
may then have to be reinitialized to clear inva­
lidated variables. To avoid problems caused by
inadvertent movement of the tuning knob, the
D. LOCK command can be programmed to be
sent to the transceiver during external control
operation.
XCVR
FUNCTION
5
,O' I
VFO-A/VFO-B SPLIT ON and OFF.
,0'2
Exchange operating freq. between
memory and VFO.
,0' 3
Write V FO data into memory.
,0'4
Lock tuning dial.
Exchange operation between V FOs A
,0'5
and B.
,0'6
Write memory data in� t o operating VFO.
(Band Up)
500
,0'7
Step up kHz
(Band
Down)
500
%8
Step down kHz
,0'9
Activate or deactivate clarifier.
,O'A
Enter new operating frequency.
,.0'8 Exchange freq. data between VFO and
memory.
MHz is stored as follows.
-45
slow to handle the required routines during data
transfer, unless the computer is equipped for
4 800-baud output.
1 0