The Unified Program and Debug Interface (UPDI) is a Microchip-proprietary interface for
external programming and on-chip debugging of a device. It is a successor to the PDI
2-wire physical interface. UPDI is a single-wire interface providing a bi-directional
half-duplex asynchronous communication with the target device for programming and
debugging purposes.
Use the pinout shown in the figure below when designing an application PCB with an AVR
with the UPDI interface included.Figure 2-4. UPDI Header Pinout
Info: Note that the reset
signal for the UPDI v2 standard is optional. The RESET signal
is required only for high voltage activation on devices where UPDI and
RESET are not on a shared pin.
Direct Connection to a Standard 6-pin 100-mil UPDI v1 Header
Use the included 100-mil 6-pin flat cable to connect directly to a board supporting the
UPDI v1 header type. Note the pin-1 marking on the cable, and ensure to line it up with
the pin-1 marking on the AVR Programming Adapter.
Direct Connection to a Standard 4-pin 100-mil UPDI v2 Header
The UPDI v2 header is directly compatible with the standard 8-pin single-row interface on
many MPLAB® Debugger/Programmer Hardware Tools. Use the included
100-mil 4-pin cable to connect the debugging/programming tool directly to the target
board supporting the UPDI v2 header type.
Important: By
design or mistake, it is possible to disable UPDI by writing to the appropriate
fuse. For details on disabling UPDI, see the FUSE sub-section of your target
devices datasheet. To enable the UPDI, a high-voltage pulse must be applied to the
RESET pin. See the UPDI section of your target
devices datasheet for details on how to apply the high-voltage pulse to the
RESET pin on your target device.
Warning: If connecting the RESET
pin to other components, be extra careful with the circuit design. Applying a
high-voltage pulse to the RESET pin can damage any other
components connected to the line. The circuit design must enable disconnection of
these components before applying the high-voltage pulse to prevent this from
happening. For instance, use a removable jumper as an example.
Table 2-4. UPDI Pin Description
MPLAB® Debugger/Programmer Hardware Tools
UPDI v1 Pin Mapping
UPDI v2 Pin
Mapping
Pin #
Pin Name
Header Pin #
Name
Pin #
Name
Pin Description
1
TVPP
1
RESET
Target RESET pin
2
TVDD
2
VCC
2
VCC
Target voltage reference
3
GND
6
GND
3
GND
Common ground
4
PGD
1
UPDI_DATA
4
UPDI_DATA
UPDI data input/output
5
PGC
6
TAUX
7
TTDI
8
TTMS
The online versions of the documents are provided as a courtesy. Verify all content and data in the device’s PDF documentation found on the device product page.
