26 0x21—adc control register (adc_control), 26 0x21—adc control register (adc_control), Bt8960 – Rockwell SoniCrafter BT8960 User Manual
Page 65
55
3.0 Registers
3.1 Conventions
Bt8960
Single-Chip 2B1Q Transceiver
N8960DSB
3.2.26 0x21—ADC Control Register (adc_control)
loop_back[1,0]
Loopback Control—Read/write binary field specifying if loopback is enabled, and the type of
loopback that is enabled. During transmitting loopback, the differential receiver inputs (RXP,
RXN) are disabled. The loopback path is intended to go from the transmitter outputs (TXP,
TXN), through the external hybrid circuit, back into the differential receiver balance inputs
(RXBP, RXBN). During silent loop back, the transmitter is turned off, and the output of the
pulse-shaping filter in the transmit section is internally connected to the input of the ADC in
the receive section.
gain[2:0]
Gain Control—Read/write binary field specifies the gain of the VGA.
7
6
5
4
3
2
1
0
–
–
loop_back[1]
loop_back[0]
–
gain[2]
gain[1]
gain[0]
loop_back[1,0]
Function
00
Normal Operation (Loop Back Disabled)
01
Hybrid Inputs Disabled (RXBP, RXBN)
10
Transmitting Loopback
11
Silent Loop Back
gain[2:0]
VGA Gain
000
0dB
001
3 dB
010
6 dB
011
9 dB
100
12 dB
101
15 dB
110
15 dB
111
15 dB