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R01UH0336EJ0102 Rev.1.02
Page 1191 of 1538
Jul 17, 2014
V850E2/PG4-L
Section 21 Clocked Serial Interface G (CSIG)
(3)
Overrun Error
This error occurs when new data are received in the reception register
(CSIGnRX0) but previously received data have not been read.
The overrun error is not generated if data reception is disabled
(CSIGnCTL0.CSIGnRXE = 0) or in master mode.
If overrun occurs:
• Interrupt CSIGnTIRE is generated
• The overrun error flag (CSIGnSTR0.CSIGnOVE) is set.
• Communication is stopped
The following figure illustrates the function.
Figure 21-23
Overrun Error Detection
The following figure illustrates an example where:
• Rx data 3 was not read
• Rx data 4 was received, but cannot be stored
Thus an overrun error occurs.
Figure 21-24
Overrun Error Detection - Example
Note
Overrun errors from trying to overwrite received data in slave mode can be
avoided through handshaking.
When handshake is used in slave mode, the receiver (slave) signals to the
transmitter (master) that it is busy. The transmitter then waits until the receiver
has read its reception register and is ready again.
Refer to Section 21.3.9, Handshake Function for details.
CSIGnTSO
Reception complete
CSIGnTSI
Data exists
Rx register
CSIG cannot store data because Rx register contains previous data
CPU does not read
Shift register
Peripheral bus
Read from CPU
Rx data
CSIGnTIR
CSIGnTIRE
Overrun error
Rx data 1
Rx data 2
Rx data 3
Rx data 4
CSIGnSTR0.CSIGnOVE
Содержание V850 Series
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