mg84fl54 Megawin Technology, mg84fl54 Datasheet - Page 77

• Manufacturer Part Number: mg84fl54
• Description: Full-speed Usb Micro-controller
• Manufacturer: Megawin Technology

17.3. Miscellaneous States
There are two SISTA codes that do not correspond to a defined TWSI hardware state, as described below.
S1STA = F8H:
This status code indicates that no relevant information is available because the serial interrupt flag, SI, is not yet
set. This occurs between other states and when TWSI is not involved in a serial transfer.
S1STA = 00H:
This status code indicates that a bus error has occurred during an TWSI serial transfer. A bus error is caused
when a START or STOP condition occurs at an illegal position in the format frame. Examples of such illegal
positions are during the serial transfer of an address byte, a data byte, or an acknowledge bit. A bus error may
also be caused when external interference disturbs the internal TWSI signals. When a bus error occurs, SI is set.
To recover from a bus error, the STO flag must be set and SI must be cleared by firmware. This causes TWSI to
enter the “not-addressed” slave mode (a defined state) and to clear the STO flag (no other bits in SICON are
affected). The SDA and SCL lines are released (a STOP condition is not transmitted).
MEGAWIN
MG84FL54B Data sheet
77