UM2448 Rev 5
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UM2448
STLINK-V3SET functional description
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7.3.2 JTAG
JTAG protocol is a Debug/Program protocol used for STM32 microcontrollers. The signals
are 3.3-volt compatible and can perform up to 21 MHz. This function is available on
MB1441.CN1 and MB1440.CN1.CN2.
The STLINK-V3SET does not support the chaining of devices in JTAG (daisy chain).
For correct operation, the STLINK-V3SET microcontroller on the MB1441 board requires a
JTAG return clock. By default, this return clock is provided through the closed jumper JP1 on
MB1441, but could also be provided from externally through CN1.9 pin (this configuration
might be necessary to reach high JTAG frequencies; in this case, JP1 on MB1441 must be
opened). In case of use with the B-STLINK-VOLT extension board, the JTAG clock loopback
must be removed from the STLINK-V3SET board (JP1 opened). For the correct functioning
of JTAG, the loopback must be done either on the B-STLINK-VOLT extension board (JP1
closed) or on the target application side.
7.3.3 SWIM
SWIM protocol is a Debug/Program protocol used for STM8 microcontrollers. JP4 and JP6
on the MB1440 board must be ON in order to activate the SWIM protocol. The signals are
available on the MB1440.CN4 connector and a voltage range from 1.65 V to 5.5 V is
supported.
7.3.4
Virtual COM port (VCP)
The serial interface VCP is directly available as a Virtual COM port of the PC, connected to
STLINK-V3SET USB connector CN5. This function can be used for STM32 and STM8
microcontrollers. The signals are 3.3-volt compatible and can perform from 720 bps to
15 Mbps. This function is available on MB1441.CN1 and MB1440.CN1.CN3. T_VCP_RX (or
RX) signal is the RX for the target (TX for the STLINK-V3SET), T_VCP_TX (or TX) signal is
the TX for the target (RX for the STLINK-V3SET).
A second Virtual COM port may be activated, as detailed later in
(Bridge
UART).
7.3.5 Bridge
functions
The STLINK-V3SET provides a proprietary USB interface allowing communication with any
STM8 or STM32 target with several protocols: SPI, I
2
C, CAN, UART, and GPIOs. This
interface may be used to communicate with the target bootloader, but may also be used for
customized needs through its public software interface.
All bridge signals can be accessed on CN9 in a simple and easy way by means of wire clips,
with the risk that signal quality and performance are lowered, especially for SPI and UART.
This depends for instance on the quality of the wires used, on the fact that the wires are
shielded or not, and on the layout of the application board.
Bridge SPI
SPI signals are available on MB1440.CN9 and MB1440.CN8. In order to reach high SPI
frequency, it is recommended to use a flat ribbon on MB1440.CN8 with all unused signals
tied to the ground on the target side.
