3.5.3
Hardware Modifications
The on-board debugger is connected to the ATtiny1627 by default. These connections must be removed before any
external microcontroller can be programmed or debugged. Cut the
GPIO straps
shown in the figure below with a
sharp tool to disconnect the ATtiny1627 from the on-board debugger.
Figure 3-9. Programming and Debugging Connections to Debugger
GPIO straps (bottom side)
Info:
Cutting the connections to the debugger will disable programming, debugging, and data streaming
from the ATtiny1627 mounted on the board.
Tip:
Solder in 0Ω resistors across the footprints or short-circuit them with solder to reconnect the signals
between the on-board debugger and the ATtiny1627.
3.5.4
Connecting to External Microcontrollers
The figure and table below show where the programming and debugging signals must be connected to program and
debug external microcontrollers. The on-board debugger can supply power to the external hardware, or use an
external voltage as a reference for its level shifters. Read more about the power supply in
.
The on-board debugger and level shifters actively drive data and clock signals (DBG0, DBG1, and DBG2) used for
programming and debugging, and in most cases, the external resistor on these signals can be ignored. Pull-down
resistors are required on the ICSP
™
data and clock signals to debug PIC
®
microcontrollers.
DBG3 is an open-drain connection and requires a pull-up resistor to function.
Remember:
• Connect GND and VTG to the external microcontroller
• Tie the VOFF pin to GND if the external hardware has its own power supply
• Make sure there are pull-down resistors on the ICSP data and clock signals (DBG0 and DBG1) to
support the debugging of PIC microcontrollers
ATtiny1627
Curiosity Nano
©
2020 Microchip Technology Inc.
User Guide
DS40002199A-page 20
