SAPHBCTL.
EXCBIAS
SAPHBCTL.
PGABIAS
TxBias
0
1
SAPHBCTL.
CH0EBSW
SAPHMCNF.LPBE
from ASQ
TxBias
SAPHBCTL.
PGABSW
from ASQ
RxBias
to
SDHS
SDHSCTL6.
PGA_GAIN[5:0]
from
ASQ
SAPHICTL.
MUXCTL
SAPHICTL.
MUXSEL
1
0
TxBias
RxBias
SAPHICTL.
DUMEN
ASQ_acquisition
ASQ_adc_arming
SDHS_adc_arming
SDHS_acquisition
SAPHBCTL.CPDA
Charge
Pump
en
PGA
CH1_IN
CH0_IN
Tx
Bias
PPG or
PPG_A
ASQ
PHY
PVSS
PVCC
CH1_OUT
CH0_OUT
TR0
TR1
0
0
1
1
from ASQ
SAPHBCTL.
ASQBSW
0
1
from ASQ
0
0
1
1
SAPHMCNF.LPBE
SAPHBCTL.
ASQBSW
SAPHBCTL.
CH1EBSW
from ASQ
0
1
from ASQ
0
0
1
1
SAPHMCNF.LPBE
SAPHBCTL.
ASQBSW
0
1
0
0
1
1
from
ASQ
SAPHMCNF.LPBE
SAPHMCNF.CPEO
SAPHMCNF.
BIMP
Rx
Bias
SAPHMCNF.
BIMP
Ground centric signal
TxBias centric signal
RxBias centric signal
PVcc/4 centric signal
PVcc/2 centric signal
PVcc/4 + Bias centric
Dummy
Input
Physical Interface (PHY) Block
510
SLAU367P – October 2012 – Revised April 2020
Copyright © 2012–2020, Texas Instruments Incorporated
Sequencer for Acquisition, Programmable Pulse Generator, and Physical
Interface (SAPH, SAPH_A)
NOTE: CH1_IN is connected to the PGA input, and CH1_OUT is connected to GND through the SWG1 switch.
Figure 21-17. Reception
The Tx bias voltage and the Rx bias voltage are programmable independently by SAPHBCTL.EXCBIAS
and SAPHBCTL.PGABIAS, respectively.
21.3.4 External Bias (XPB0 and XPB1 on SAPH_A)
The SAPH_A module features external bias terminals XPB0 and XPB1. Set SAPH_AICTL0.XPB0FEN=1
to enable the analog bias function on the XPB0 terminal. Use SAPH_AICTL0.XPBSW0 to turn the bias
switch on or off. If SAPH_AICTL0.XPB0FEN=0 the terminal is used as a regular digital port pin. On
SAPH_AICTL0.XPB0FEN=1 and SAPH_AICTL0.XPBSW0=1 the PGA bias voltage is provided on XPB0.
XPB1 works the same way with its corresponding control bits.
The XPB0 and XPB1 terminals provide auxiliary voltages for optional external analog circuits with high
impedance inputs.
Note:! The XPB0 and XPB1 control logic requires the HSPLL clock to be running for operation.
21.4 Acquisition Sequencer (ASQ)
The entire measurement sequence can be controlled by user software (called register mode), by ASQ
without any CPU intervention (called auto mode) or by ASQ without any CPU intervention (called ultra low
power bias mode). The auto mode helps reduce the measurement power consumption, because the CPU
can stay in LPM0 during the measurement sequences. The ASQ is a state machine that can be used to
control the entire measurement sequence.
shows the ASQ block diagram. In auto mode a
mixed operation of register control and ASQ control is possible for various signal chain elements. In ultra
low power bias mode all control is obtained by the ASQ.