Rev 1.1 | SC5520A & SC5521A
Hardware Manual
SignalCore, Inc.
26
Register 0x1D DIRECT_ATTEN
This register allows the user to set the LF or HF attenuators manually, thus overriding calibrated values.
Bit Type Name
Width Description
[7:0]
WO
Value
8
0.25 dB LSB for RF attenuators up to 63.75 dB, 1
dB LSB for LF attenuators up to 32 dB.
[23:8]
WO
Unused
16
Set to zeros.
Query Registers
These are request for data registers, in that a request for certain data is made by writing to the specific
register first, followed by reading back the requested data. Some registers may require instruction data to
specify the type of data to return, while others do not need any. For example, the GET_RF_PARAMETERS
(0x20) returns sweep dwell time, rf1 frequency, list start frequency, etc.; this depends on the request
instruction byte.
Returned data length is always 8 bytes (64 bits), with the first byte being the most significant (MSB). Not all
8 bytes are valid, some have 7, some 4, and others 2. It is important that all 8 bytes are read in order to
clear the interface buffers.
Table 7. Query Registers
Register Name
Register
Address
Serial
Range
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
FETCH_RF_PARAMETERS
0x20
[7:0]
Open
Open
Open
Open
Parameter
FETCH_TEMPERATURE
0x21
[7:0]
Open
Open
Open
Open
Open
Open
Open
Open
RETCH_DEVICE_STATUS
0x22
[7:0]
Open
Open
Open
Open
Open
Open
Open
Open
FETCH_DEVICE_INFO
0x23
[7:0]
Info
FETCH_LIST_BUFFER
0x24
[7:0]
Buffer Address [7:0]
[15:8]
Zeros [15:12]
Buffer Address [11:8]
[23:16]
Zeros [23:16]
FETCH_DAC_VALUE
0x25
[7:0]
Zeros[7:1]
DAC
Select
SERIAL_OUT_BUFFER
0x26
[7:0]
Zeros [7:0]
RESERVED
0x27
[7:0]
FETCH_SENSOR_VALUE
0x28
[7:0]
Zeros [7:0]
Register 0x20 GET_RF_PARAMETERS (1 Byte sent, 8 Bytes received)
Write to this register the required RF parameter to query from the device.
