NEC V850ES/F 3-L Series User Manual page 435

Clocked Serial Interface (CSIB)
(4)
Note
CBnSTR - CSIBn status register
CBnSTR is an 8-bit register that displays the CSIBn status.
This register can be read or written in 8-bit or 1-bit units, but the CBnTSF flag
is read-only.
Reset input clears this register to 00H.
In addition to reset input, the CBnSTR register can be initialized by clearing (0)
the CBnCTL0.CBnPWR bit.
After reset 00H R/W
< >
CBnSTR CBnTSF
CBnTSF
0
Communication stopped
1
Communicating
• During transmission, this register is set when data is prepared in the CBnTX
register, and during reception, it is set when a dummy read of the CBnRX register
is performed.
When transfer ends, this flag is cleared to 0 at the last edge of the clock.
CBnOVE
0
No overrun
1
Overrun
• An overrun error occurs when the next reception starts without performing a CPU
read of the value of the receive buffer, upon completion of the receive operation.
The CBnOVE flag displays the overrun error occurrence status in this case.
• The CBnOVE flag is cleared by writing 0 to it. It cannot be set even by writing 1 to it.
In case of an overrun error, the reception interrupt INTCBnR behaves different,
depending on the transfer mode:
• Continuous transfer mode
The reception interrupt INTCBnR is generated.
• Single transfer mode
No interrupt is generated.
In either case the overflow flag CBnSTR.CBnOVE is set to 1 and the previous
data in CBnRX will be overwritten with the new data.
User's Manual U18743EE1V2UM00
Address: CB0STR FFFFFD03H, CB1STR FFFFFD13H
0 0 0
Communication status flag
Overrun error flag
Chapter 16
0 0 0
< >
CBnOVE
435