| USX2
serial interface details (version 4): PRELIMINARY
The USX2 user interface is accessed through the four parallel
pins (P0/serial through P3).
It has four operating modes:
1. Parallel
Frequency of operation is selected as one of 16 (chans
0-15), by means of a 4 bit inverted value applied to P0-P3.
The P0 pin will also respond to a LOCKSERIALMODE datastream
(inverted RS232, 9600 baud), which will cause the radio
to enter serial mode. In parallel mode, the IDENT command
string is still decoded, but the unit remains in parallel
mode.
2. Serial
Frequency of operation, radio set up, power output and
various other parameters are controlled by command strings
sent to P0. Pin P3 functions as a 'readback' port while
P1,2 are not used in this mode.
In this mode, decimal values are used (to simplify direct
manual programming via a terminal)
Commands include :
| Commands |
Function |
Note |
| : |
empty command buffer |
|
| ? or / |
read back buffer contents |
|
| <backspace> |
delete last character |
|
| <cr> |
process buffer |
|
| |
|
|
| PARALLEL |
return to the basic,
parallel mode (and turn modem off) |
|
| DUMP |
read back contents of
eeprom (output on P3) |
|
| MODEM |
activate 1200 baud modem
|
# |
| NOMODEM |
de-activate 1200 baud
modem |
# |
| |
|
|
| DEFCH ccc |
set default channel
(non-volatile) |
# |
| DEFPOW pp |
set default tx power
(non-voltatile) |
# |
| |
|
|
| CHAN ccc |
jump to channel (volatile) |
|
| POWER pp |
select tx power (volatile) |
|
| RSSI |
single read of RSSI
(output on P3) |
|
| |
|
|
| SHORT |
enter short command
mode |
# |
(The following commands are used to set up the radio operating
characteristics, and should be viewed with caution. Especially
the CALPOWER command, which initiates a multiple write operation
to the power calibration table )
| Commands |
Function |
Note |
| NDIV nnnnn |
force N divider value
(volatile) |
|
| RDIV rrrrr |
force R divider value
(volatile) |
|
| |
|
|
| RLOAD rrrrr |
Set R divider value |
# |
| OFFSET ooooo |
Set RX offset |
# |
| LOAD aa nnnnn |
Set N values for first
16 channels |
# |
| START nnnnn |
Set N value
for ch 16 |
# |
| STEP i |
Set increment for table |
# |
| LIMIT ccc |
Set highest permitted
channel number |
# |
| |
|
|
| SETPOW eee |
Set maximum power output
(100mW) |
|
| CALPOWER
(etc) |
(see factory
procedures for more details) |
|
| |
|
|
| TEST |
Generate
a 250Hz test modulation (only fuctions in TX mode, cancelled
by sending a <cr> byte) |
|
| |
|
|
| IDENT |
Readback a single byte,
depending on current mode: |
|
| |
Parallel: P |
|
| |
Serial: S |
|
| |
Short: 1 |
|
| |
Modem: M |
|
(Channels 0-15 are individually programmed by the LOAD
operation. Channels 16-127 are a consecutive table, using
the START value as a start point (=channel 16) and increasing
the N value by STEP with each increase in channel number)
ccc = a channel number from 00 to 127
aa = a two digit channel number from 00 to 15
nnnnn = synthesizer N register value, (up to 65535)
rrrrr = synthesizer R register value, (up to 16383)
pp = power setting value (0 - 30)
i = table step (increments of N) (0-7)
ooooo = receive mode frequency offset
eee = power calibration figure
N = channel frequency /
(13MHz / R)
13MHz / R = 25KHz , so R
= 520 (usually)
receive OFFSET = 21.4MHz
/ (13MHz / R) , so = 856 (usually)
- A pause of at least 50mS must be allowed after operations
which result in eeprom programming operations (all except
NDIV, RDIV, GOTO, PSET and RSSI). This allows the programming
cycle to complete.
- Instructions marked ' # ' output
a three byte ' OK<cr> ' sequence after sucessfully
completing their eeprom programming cycles
- When first powered up, the unit will operate on channel
and output level specified by the last CHAN and POWER
instructions, irrespective of previous NDIV, RDIV, CHAN
or PSET operations)
3. Short
A limited range of radio functions are controlled by sending
a single byte to P0
| Commands |
Function |
Note |
| 0 - 127 |
select channel |
volatile |
| 128 - 159 |
select power ( = byte -128) |
volatile |
| 200 |
single read of RSSI |
output on P3 |
| 201 |
single byte read, as for IDENT
command |
|
| 222 |
reception of 16 consecutive 222
bytes returns radio to serial
mode |
|
4. Modem
Commands are interpreted as in SERIAL mode (and 'short'
mode may be selected.) In this mode the unit operates as
a simple 1200 baud packet modem, with TXD (in) on P2 and
RXD (out) on P1.
The TXE pin does not control
tx switching in this mode, but rather the presence of valid
data in the tx buffer initiates a transmit burst. No handshaking
is provided, and the unit has a sufficient over-link data
rate to transparently 'stream' continuous data. Error correction,
re-transmission of corrupt packets and addressing are not
provided.
This mode is compatible with other Radiometrix 'i 1200'
mode equipment, including the narrow band eval kit.
NOTES:
- The LOCKSERIALMODE (and FAST) commands are non-volatile.
Once a serial mode is selected, the unit will power up
in this mode until a PARALLEL command is received.
- The command interpreter IS case sensitive. Use upper
case.
- Spaces are optional (they are not decoded), provided
the command line does not exceed 16 characters.
- When manually programming this unit we recommend setting
your terminal to local echo. The 'backspace' key functions
normally.
- All serial communications use 9600baud 'inverted RS232'
8 bit data, no parity, 1 start bit, 1 or 2 stop bits
- A simple 'driver' program will be made available to
simplify programming of these units, if desired.
- RSSI read operations only function correctly if the
unit is in RX mode (TXE
pin is high or floating)
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