Microchip Technology MPLAB ICD 5 - Page 25

Connecons
User Guide
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DS-50003529B - 25
The RSTPINCFG[1:0] fuses have the following congurations, as described in the data sheet. The
practical implications of each choice are given here.
Table 3-10. RSTPINCFG[1:0] Fuse Conguraon
RSTPINCFG[1:0] Conguration Usage
00
GPIO General purpose I/O pin. To access UPDI, a 12V pulse must be applied to this pin. No
external Reset source is available.
01
UPDI Dedicated programming and debugging pin. No external Reset source is available.
10
Reset Reset signal input. To access UPDI, a 12V pulse must be applied to this pin.
11
Reserved NA
Note: Older AVR devices have a programming interface, known as “High-Voltage Programming”
(both serial and parallel variants exist). In general, this interface requires 12 V to be applied to the /
RESET pin for the duration of the programming session. The UPDI interface is an entirely dierent
interface. The UPDI pin is primarily a programming and debugging pin, which can be fused to have
an alternative function (/RESET or GPIO). If the alternative function is selected then a 12 V pulse is
required on that pin to re-activate the UPDI functionality.
Note: If a design requires the sharing of the UPDI signal due to pin constraints, steps must be taken
to ensure that the device can be programmed. To ensure that the UPDI signal can function correctly,
as well as to avoid damage to external components from the 12 V pulse, it is recommended to
disconnect any components on this pin when attempting to debug or program the device. This can
be done using a 0 Ω resistor, which is mounted by default and removed or replaced by a pin header
while debugging. This conguration eectively means that programming should be done before
mounting the device.
3.3.5.6.2 Connecng to an AVR UPDI Target
The recommended pinout for the 6-pin UPDI connector is shown in 3.3.5.6.3. AVR UPDI Pinout.
Connection to a 6-pin 100-mil UPDI Header
Use the AVR 6-pin adapter board to connect to a standard 100-mil UPDI header.
Connection to a 6-pin 50-mil UPDI Header
Use the AVR 6-pin mini adapter board to connect to a standard 50-mil UPDI header.
3.3.5.6.3 AVR UPDI Pinout
When designing an application PCB, which includes a Microchip AVR with the UPDI interface, the
pinout shown below should be used.
Figure 3-15. UPDI Header Pinout
Table 3-11. UPDI Pin Mapping
AVR PORT Pin Target Pins Microchip STK600 UPDI Pinout
Pin 1 (TCK)
Pin 2 (GND) GND 6
Pin 3 (TDO) UPDI_DATA 1
Pin 4 (VTG) VTG 2