CY3663 datasheet(86/92 Pages) CYPRESS

86 / 92 page

CY7C67200

Document Number: 38-08014 Rev. *I

Page 86 of 92

3. UART Does Not Recognize Framing Errors

■ Problem Definition

The UART is not designed to recognize framing errors.

■ Parameters Affected

UART serial communications.

■ Trigger Conditions

Some platforms can cause EZ-OTG to see a string of NULL characters and cause the UART to get out of sync.

■ Scope of Impact

This can cause the UART to lose connection with the host during serial communications. One example of this is if the UART is

used as the debug port to the PC. This problem has occurred on, but is not limited to, Dell machines running WinXP or Win2k.

■ Workaround

For general use, there is no workaround. If this problem is experienced while debugging, try running the debugger on a different

Host (PC/OS). Otherwise the USB port can be used for the debugging interface.

■ Fix Status

No fix is currently planned for future silicon versions.

4. UART Does Not Override GPIO Control Register

■ Problem Definition

When the UART is enabled, the GPIO Control Register still has control over GPIO 6 (UART RX pin). When enabled, the UART

should override the GPIO Control Register, which defaults to setting the pin as an input.

■ Parameters Affected

UART serial communications.

■ Trigger Conditions

Enabling UART

■ Scope of Impact

GPIO 6 UART RX pin is controlled by GPIO Control Register and defaults to an input. The UART mode does not override the GPIO

control register for this pin and can be inadvertently configured as an output.

■ Workaround

Ensure the GPIO Control Register is written appropriately to set GPIO6 as an input when the UART is enabled.

■ Fix Status

No fix is currently planned for future silicon versions.

CY3663 Datasheet(PDF) 86 Page - Cypress Semiconductor