UPSD3422_06 Datasheet, PDF (287/293 Pages) STMicroelectronics – Turbo Plus Series Fast Turbo 8032 MCU with USB and Programmable Logic

uPSD34xx
34 Important notes
Important notes
The following sections describe the limitations that apply to the uPSD34xx devices and the
differences between revision A and B silicon.
34.1
USB interrupts with idle mode
Description
An interrupt generated by a USB related event does not bring the MCU out of idle mode for
processing.
Impact On Application
Idle mode cannot be used with USB.
Workaround
Revision A - None identified at this time.
Revision B - Corrected in silicon so that a USB interrupt that occurs will bring the MCU out of
idle mode.
34.2
USB Reset Interrupt
Description
When the MCU clock prescaler is set to a value other than f_MCU = f_OSC (no division), a reset
signal on the USB does not cause a USB interrupt to be generated.
Impact On Application
An MCU clock other than that equal to the frequency of the oscillator cannot be used.
Workaround
Revision A - The CPUPS field in the CCON0 register must be set to 000b (default after
reset). The 3400 USB firmware examples set CCON0 register to 000b.
Revision B - Corrected in silicon so that when an MCU clock prescaler is used, a reset
signal on the USB does generate an interrupt.
34.3
USB Reset
Description
A USB reset does not reset the USB SIE's registers.
Impact On Application
A USB reset does not reset the USB SIE's registers as does a power-on or hardware reset.
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