Hardware Configuration

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SPRUI77C – August 2016 – Revised March 2019

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LAUNCHXL-F28379D Overview

5.1

ADC Resolution

The F28379D had 4 independent 16-bit/12-bit ADCs. The resolution of each ADC is SW selectable.

ADCA, ADCB, and ADCC are all routed to the BoosterPack headers for use with different booster packs.

Most BoosterPacks will use the ADC in 12-bit mode which supports Single Ended (SE) inputs. ADCD has

been routed to a special side connector with ability to drive through a differential amplifier to support 16-bit

mode with Differential Ended (DE) inputs.

5.2

Power Domain

The LaunchPad has several different power domains to enable JTAG Isolation. Jumpers JP1, JP2, JP3

control JTAG Isolation, supply GND, 3.3 V and 5 V to the rest of the board. There are also other jumpers

that provide different methods for powering the device.

Table 1 describes the different methods by which 3.3 V can be supplied to the device. It can be derived

from USB in configuration 1. Here, the on-board regulator steps the 5 V from the USB port down to 3.3 V

to be used by the XDS100v2 debug probe as well as connected to the device side of the LaunchPad

through JP1. Configuration 1 is a non-isolated configuration. Alternately, in configuration 2 the debugger

and USB connection are isolated from the device. The 3.3 V source must be provided externally through

the BoosterPack headers or through J10.

Table 1. Supplying the LaunchPad With 3.3 V

Configuration

JP1

JP2

USB

External 3.3 V

JTAG/USB

Isolation Status

1

Yes

Yes

Yes

No

Not Isolated

2

No

No

Don't Care

Yes

Isolated

The LaunchPad also has a 5 V power rail. It can be supplied directly from the USB (not isolated)

generated from a 3.3 V to 5 V step-up regulator through JP6, or supplied externally through the

BoosterPack Headers or J16. Table 2 describes these various configurations.

The debug probe and USB are not isolated in configuration 1 since JP2 and JP3 are connected. The 5 V

supply is coming from the USB directly to the device side of the LaunchPad and can be used to power

other devices connected to the BoosterPack headers. In this configuration, do not connect JP6 as there

may be contention between the 5 V from the USB (JP3) and the 5 V from the on-board step-up regulator,

U12.

Configuration 2 is an isolated configuration where 3.3 V is supplied any way other than through JP1. In

this configuration, JP6 is connected allowing the 3.3 V to be stepped up to 5 V with the on-board step-up

regulator, U12. In this configuration ensure that no other 5 V source is connected to the BoosterPack

headers or through J16.

Configuration 3 is another isolated configuration since JP2 and JP3 are not connected. With JP6

disconnected, 5 V must be supplied through an external connection on the BoosterPack headers or J16.

Notice that this configuration does not rely on the 3.3 V supply being powered to provide the 5 V. To

supply 3.3 V to the device in an isolated configuration, see Table 1.

Table 2. Supplying the LaunchPad With 5 V

Configuration

JP2

JP3

JP6

External 5 V

USB

JTAG/USB

Isolation Status

1

Yes

Yes

No

No

Yes

Not Isolated

2

No

No

Yes

No

Don't Care

Isolated

3

No

No

No

Yes

Don't Care

Isolated