Computex FP-40 - 20-Pin 1.27 Mm-Pitch Connector; ③ SWD Interface

Technical Information on On-board Flash Programmer FP-40 Aug. 31, 2023 (Second edition)
8
■ 20-pin 1.27mm-pitch connector
Target connector specifications
(Top view on the target board)
Recommended connector
Manufacturer: Samtec, Inc.
Model: FTSH-110-01-L-DV-K
(For detailed dimensions of the connector, refer to the documentation by manufacturer of the
connector.)
*Please refer the pin configuration diagram above and make sure that the connector is in the right direction
before connecting.
Please check the pin number in the signal table above and make sure the signal and the pin numbers
match.
This connector does not support the power supply function to the target.
③ SWD interface
The signal table and target connection reference diagram when connecting a 20-pin 1.27mm pitch connector with SWD
interface are shown below.
Signal table
Pin
No.
Signal
Input/
Output
*1
Pin
No.
Signal
Input/
Output
*1
1 VTref
*2
Output 2 SWDIO
Input/
Output
3
GND
4
SWCLK
Input
5
GND
6
SWO
*3
Output
7
Key
*6
8
NC
NC
9
GND
10
SRSTn
*4
Input
11
GND
*5
12
TraceClk
*3
Output
13
GND
*5
14
TraceD0
*3
Output
15
GND
16
TraceD1
*3
Output
17
GND
18
TraceD2
*3
Output
19
GND
20
TraceD3
*3
Output
*1
: Input/output is denoted for the target system.
*2
: Connect the I/O power supply of the CPU to VTref.
*3
: Unused. NC.
*4
: Connect the reset signal to the connected CPU with a wired
OR circuit or an OR circuit. The SRSTn signal is an open
collector output.
*5
: In some target systems, this pin may be assigned as a power
supply pin. This product is GND, so do not connect it to the
power line (or leave it unconnected).
*6
: Intended for protection against erroneous insertion.
Target connection reference diagram
 To prevent malfunction, the length of wirings from the CPU to the target connector should be kept as short as possible.
 If the waveform disturbance exceeds the device specifications, suppress the disturbance by inserting a damping resistor into the signal line or use
other means.