UPSD3422 datasheet(290/293 Pages) STMICROELECTRONICS

290 / 293 page

Important notes

uPSD34xx

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an ACK. The host will resend the SETUP packet a number of times and if an ACK is not

received from the uPSD3400, the host will issue a USB reset and then enumerate it again.

Upon detecting a USB reset, the uPSD3400 firmware will reset and initialize the USB SIE

putting the hardware back into the reset/initialized state so that when the next SETUP

packet is received, the uPSD3400 will respond with an ACK to the host.

Impact On Application

If this occurs during enumeration, the impact is minimal as the host will retry the

enumeration. If it happens after enumeration, the communication will break down between

the host application and the uPSD3400 and will need to be re-established after the

uPSD3400 is reset and enumerated again. In extremely noisy environments, the

uPSD3400 may not communicate well over USB with the host application.

Workaround

Revision A and B - None identified at this time.

34.10

MCU JTAG ID

Description

MCU JTAG ID changed to differentiate revision A from revision B silicon through the JTAG

port. The PSD JTAG ID remains the same.

Revision A MCU JTAG ID - 0x0451F041

Revision B MCU JTAG ID - 0x1451F041

Impact On Application

There will be no impact on the application. The impact will be to JTAG production

programming equipment that may need to distinguish between revision A and B MCU silicon

if the firmware is different depending on the revision level.

34.11

PORT 1 Not 5-volt IO Tolerant

Description

The port P1 is shared with the ADC module and as a result Port P1 is not 5V tolerant.

Impact On Application

5V devices should not be connected to port P1.

Workaround

Revision A and B - Peripherals or GPIO that require 5-Volt IO tolerance should be mapped

to Port 3 or Port 4.

UPSD3422 Datasheet(PDF) 290 Page - STMicroelectronics