Texas Instruments TLV320DAC26EVM, Руководство пользователя, Страница: 18 / 38

Jumpers
3-2
3.1 Jumpers
Table 3−1 shows the function of each jumper on the EVM.
Table 3−1. Jumper/Function Reference
Reference
Designator
Setting Function Factory Default Subsection
JMP1 1 to 2
Differential (MICIN and AUX) microphone
input (for sidetone only)
Not installed 3.1.1
JMP2
1 to 2 MIC BIAS from fixed resistor
2 to 3 3.1.2 JMP2
2 to 3 MIC BIAS from DAC26
2 to 3 3.1.2
JMP3 1 to 2 A1 select for EEPROM Installed 3.1.3
JMP4
1 to 2 PWR select: USB powered
1 to 2 3.1.4 JMP4
2 to 3 PWR select: External power supply
1 to 2 3.1.4
JMP5 − JMP8
Removed Power is not provided to DAC26
Installed 3.1.5 JMP5 − JMP8
Installed Power is provided to DAC26
Installed 3.1.5
JMP9
1 to 2 DAC26 uses 3.3-V IOVDD
1 to 2 3.1.6 JMP9
2 to 3 DAC26 uses 1.8-V IOVDD
1 to 2 3.1.6
3.1.1 Differential Microphone Input
The microphone signal can be input to the DAC26 through the MICIN or AUX,
if the signal is single ended. In single-ended mode, JMP1 should be removed.
The microphone signal, if differential, can be connected to the DAC26 through
J5 and to the DAC26 MICIN and AUX pins. In differential mode, JMP1 should
be installed.
3.1.2 MIC BIAS Selection
JMP2 selects the microphone bias to come from the DAC26 itself or from an
external resistor, R11, which is not installed on the DAC26EVM board. If an
external bias is needed, the appropriate size resistor can be soldered into the
R11 location on the board and JMP2 set to connect between positions 1 and
2. If MIC BIAS is not required, do not install the jumper top for JMP2 in any
position.
3.1.3 EEPROM A1 Select
The DAC26EVM loads its firmware from an onboard EEPROM. In order to use
the firmware in this EEPROM, its address A2, A1, A0 should be 000b. JMP3
is used to pull the A1 line low so that the EEPROM is selected. When A1 is not
low, the EEPROM is not able to interface to the onboard TAS1020B processor.
This jumper can be removed when firmware updates are to be made.
3.1.4 Power Supply Selection
The DAC26EVM can be powered from the USB port directly, or an external
power supply can be provided through J9 or J10. JMP4 selects between the
USB and external power sources.