st20-gp6 STMicroelectronics, st20-gp6 Datasheet - Page 87

• Manufacturer Part Number: st20-gp6
• Description: Gps Processor
• Manufacturer: STMicroelectronics

15.4.1 Using the ASC interrupts when fifos are disabled
When fifos are disabled, the ASC provides three interrupt requests to control data exchange via the
serial channel:
For single transfers it is sufficient to use the transmitter interrupt (TxEmpty), which indicates that
the previously loaded data has been transmitted, except for the stop bit.
For multiple back-to-back transfers using TxEmpty would leave just one stop bit time for the han-
dler to respond to the interrupt and initiate another transmission. Using the transmit buffer interrupt
(TxHalfEmpty) to reload transmit data allows the time to transmit a complete frame for the service
routine, as ASCTxBuffer may be reloaded while the previous data is still being transmitted.
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TxHalfEmpty is activated when data is moved from ASCTxBuffer to the txshift register.
TxEmpty is activated before the stop bit is transmitted.
RxBufFull is activated when the received frame is moved to ASCRxBuffer.
2
3
4
5
8
9
0
1
6
7
TimeoutNotEmpty
TxHalfEmpty
OverrunError
RxHalfFull
TimeoutIdle
ParityError
FrameError
TxFull
RxBufFull
TxEmpty
ASCStatus
Figure 15.4 ASC status and interrupt registers
TimeoutNotEmpty IE
TxHalfEmpty IE
OverrunError IE
ParityError IE
FrameError IE
RxHalfFull IE
TimeoutIdle IE
RxBufFull IE
ASCIntEnable
TxEmpty IE
ASC_interrupt
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