Hardware layout and configuration
UM2271
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DocID030906 Rev 2
all peripherals related I/Os to inactive level (input pull-down or input is good option
according to I/Os).
3. Disconnect JP9 to 5 V from LD8 power LED, disconnect JP10 (or put it in 2-3
position), power off OCTOSPI (remove SB23/SB24) and configure related I/Os as input
pull down.
4. Peripherals can be setup by FW to reach power down mode. All I/Os must be
configured in non-consuming states. Set MFX_V3 to sleep mode, get SD card out of its
socket slot. Set the Audio Codec in power down.
10.5
TAG and SWD
One TAG interface footprint CN8 is reserved on 32L4R9IDISCOVERY and is usable to
debug and program the on-board MCU.
Note:
Micro switch SW1 must be put in Off position. R24 and R31 must be disconnected.
The SWD 6-pin header CN5 added on 32L4R9IDISCOVERY, connected to on board ST-
LINK MCU, is usable to debug and program an external MCU.
VDD from the external board is 1.8 V or 3.3 V, thanks to the on board voltage converter.
SW1 is accessible on bottom side of 32L4R9IDISCOVERY. By default, SW1 is in On
position. To put micro switch in Off position, just push away the switch from ON position as
shown in
Table 2. JP10: VDD_STL setting
Jumper
Setting
Description
JP10
Default setting.
VDD_STL gets power from 32L4R9IDISCOVERY. ST-LINK is
then usable to program the on-board MCU.
VDD_STL gets power from external through CN5. ST-LINK is
then usable to program an external MCU.
Table 3. SW1 switch setting
Switch
Setting
Description
SW1
Default setting.
SW1 switch is On.
SW1 is Off.
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