Stm32H5 Debug Authentication Protocol Description; Physical Link; Stm32H5 Debug Authentication Protocol Overview; Figure 4. Dbgmcu Usage - ST STM32H5 Series Getting Started

5

STM32H5 debug authentication protocol description

5.1

Physical link

Host and STM32H5 use JTAG or SWD physical connection over access point 0.
Using access point 0, debug transactions only access a very limited part of the STM32H5, for example, the
DBGMCU IP.
Host
DBGMCU acts as a mailbox between the host and the STM32 device.
The debug host uses JTAG/SWD to write a word within the DBGMCU_DBG_AUTH_HOST register in order to send
messages to the debug authentication service of the STM32 device.
The debug authentication service of the STM32 device reads the same register to get the messages.
The debug authentication service writes a word within the DBGMCU_DBG_AUTH_DEV register in order to send a
word to the debug host.
The debug host uses JTAG/SWD to read a single word from the DBGMCU_DBG_AUTH_DEV register.
The debug host and the STM32 device use the DBGMCU_DBG_AUTH_ACK register for acknowledgment of
exchanges from the STM32 device to the debug host and from the debug host to the STM32 device.
For more details about the DBGMCU register, refer to document [2].
Host and STM32H5 use the Arm
Once the debug authentication sequence is completed, STM32H5 debug authentication opens access point 1 and
the debug host can establish the debug connection with it.
With access point 1, the debug host accesses all STM32H5 resources granted by the debug reopening context
request.
5.2

STM32H5 debug authentication protocol overview

STM32H5 debug authentication services use the Arm
The STM32CubeProgrammer embeds this protocol and can be used without extra effort.
This protocol specifies five commands:
Command constant
AN6008 - Rev 1
Figure 4.
Read 32 bits word
JTAG/SWD
Write 32 bits word
®
PSA ADAC protocol over DBGMCU mailbox.
0x0001
0x0002
STM32H5 debug authentication protocol description
DBGMCU usage
DBGCMU_DBG_AUTH_DEV
DBGCMU_DBG_AUTH_HOST
®
PSA ADAC protocol depicted by document [1].
Command name
ADAC_DISCOVERY_CMD
ADAC_AUTH_START_CMD
STM32H5
Write 32 bits word
Cortex
Read 32 bits word
Description
The host requests information about the
debug target (STM32H5) using with this
command.
The host sends this command to start
the authentication sequence. Its primary
purpose is for the target to provide a
random 256-bit challenge vector used to
prevent replay attacks.
AN6008
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