SC5313A Operating & Programming Manual
Rev 1.0.2
14
To write to the device through USB transfers such as bulk transfer, it is important to send the data with
the register byte first, followed by the most significant bit (MSB) of the data bytes. For example, to set
the attenuation value of ATTEN#2, the byte stream would be [0x13][15:8][7:0].
Initializing the Device
INITIALIZE (0x01)
- Writing 0x00 to this register will reset the device to the default power-on state.
Writing 0x01 will reset the device but leave it in the current state. The user has the ability to define the
default startup state by writing to the
STORE_STARTUP_STATE (0x1D)
register, described later in this
section.
Setting the System Active LED
SET_SYSTEM_ACTIVE (0x02)
- This register simply turns on the front panel “active” LED with a write of
0x01, or turns off the LED with a write of 0x00. This register is generally written when the device driver
opens or closes the device.
Setting the RF Frequency
RF_FREQUENCY (0x10)
- This register provides the device frequency information to set up the filters
appropriately. Data is sent as a 40 bit word with the LSB in Hz.
Setting RF Input RF Amplifiers
RF_AMPLIFIER (0x12)
- This register enables or disables the RF amplifiers. Setting bit 0 low (0) disables
RF amplifier. Setting bit 0 high (1) enables RF amplifier. Bit 1 selects the amplifier; 0 for RF AMP#1, 1 for
RF AMP#2.
Setting the RF Attenuation
RF_ATTENUATION (0x13)
– Each of the attenuators is a 5 bit digital step attenuator with 1 dB per LSB.
Data is sent in 2 bytes; byte1 and bits [1:0] specifies the attenuator to program, and byte0 and bit [4:0]
specifies the attenuation value.
Setting the RF Path
RF_PATH (0x14)
– Setting bit 0 low selects the main RF input path, while high will select the RF auxiliary
path.
Selecting the RF Filter
RF_FILTER_SELECT (0x15)
– There are 9 RF filters to select from to improve RF input second harmonic
suppression. Bits [3:0] are used.
