BUF16821EVM-USB Software
13
SBOU106A – May 2011 – Revised May 2016
Copyright © 2011–2016, Texas Instruments Incorporated
BUF16821EVM-USB Evaluation Board and Software Tutorial
Table 5. USB_DIG_Platform Jumper Functions (continued)
Jumper
Default
Purpose
(1)
CAUTION:
Adjusting outside of this range will damage the EVM.
JUMP13
REG
Uses the regulator output to generate the V
DUT
supply. The USB bus can be used as the V
DUT
supply.
JUMP14
9V
Uses the external power (9V as opposed to the
bus).
JUMP17
BUS
While in the BUS position V
DUT
operation is normal.
While in the V
RAW
position the V
DUT
supply is
connected to an external source. This configuration
allows for any value of V
DUT
between 3V and 5V.
(1)
JUMP18
V
DUT
Connects the pull-up on GPIO to the V
DUT
supply or
the V
CC
supply.
3.7
BUF16821EVM-USB Features
This section describes some of the hardware features present on the BUF16821EVM-USB test board.
3.7.1
BKSEL: OTP Bank Selection Switch
The BKSEL switch located on the BUF16821EVM-USB Test Board selects the memory bank to be used
when operating the EVM. Bank 0 selects the gamma curve that is stored in Bank_0 of the BUF16821.
Bank 1 selects the gamma curve that is stored in Bank_1 of the BUF16821. This switch also determines
the OTP bank that is written to by the BUF16821EVM-USB software. Note that this switch is not effective
if JMP4 is set to EXT.
3.7.2
JMP1: I
2
C SCK Control Setting
Jumper JMP1 selects where the BUF16821 digital supply pin is connected. If JMP1 is set in the INT
position, the VSD pin is connected to the switchable VDUT signal generated from the USB DIG Platform.
This voltage can be set to either 3.3V or 5V depending on how JUMP9 on the USB DIG Platform is set.
While JMP1 is set to the INT position, the VSD Power button on the BUF16821 software is able to control
whether the VDUT supply voltage is turned on or off.
When JMP1 is set in the EXT position, an external supply connected to terminal T2 can be used to
provide the digital supply voltage for the BUF16821.
3.7.3
JMP2: V
SD
Control Setting
Jumper JMP2 selects where the BUF16821 I2C SDA pin is connected. If JMP2 is set in the INT position,
the I2C data signal is generated from the I2C_SDA_ISO signal from the USB DIG Platform.
When JMP2 is set in the EXT position, an external source connected to SDA pin of terminal T4 can be
used to provide the I2C SDA signal for the BUF16821.
3.7.4
JMP3: BKSEL Control Setting
Jumper JMP3 selects where the BUF16821 I2C SCL pin is connected. If JMP3 is set in the INT position,
the I2C clock signal is generated from the I2C_SCK_ISO signal from the USB DIG Platform.
When JMP3 is set in the EXT position, an external source connected to SCL pin of terminal T4 can be
used to provide the I2C SCK signal for the BUF16821.
3.7.5
JMP4: I
2
C SDA Control Setting
Jumper JMP4 determines how the OTP memory bank selection is controlled. There are two settings JMP4
can be set to. Position INT specifies that control of the BKSEL pin is handled on the BUF16821 Test
Board by the BKSEL switch. Position EXT for JMP4 allows for an external control signal connected to
terminal T3 to determine the selection of which OTP bank to be used.