Fujitsu FR81S User Manual
CHAPTER 40: MULTI-FUNCTION SERIAL INTERFACE
6. Operation of CSIO
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER : MULTI-FUNCTION SERIAL INTERFACE
FUJITSU SEMICONDUCTOR CONFIDENTIAL
188
6.1.7.
Timing of Chip Select Error Generation and Flag
Setting
Setting
Chip select error will be generated when the number of frames which have been transmitted is less than the
setup value specified by the TBYTE and no valid data is present in the transmission data register (TDR)
(SSR:TDRE="1") after one frame is transmitted while in master mode (SCR:MS="0"). This error will also
be generated when chip select pin becomes inactive while transmitting in slave mode (SCR:MS=1).
Master Mode (SCR:MS="0")
Chip select error will be generated with transfer byte error enabled (TBEEN="1") and any of following
events when no valid data is present in the transmission data register (TDR) (SSR:TDRE="1") before
transmitting data frame specified by the TBYTE.
⋅
Chip select is used
⋅
Synchronous transmission with the serial timer is used
⋅
Transmission activated by external trigger is used
In this case, when chip select error interrupt is enabled (SACSR:CSEIE="1"), a transmission interrupt will
be generated.
Figure 6-6 Chip Select Error Generation Timing
CSE
1
st
Byte
2
nd
Byte
TDRE
Transmission data
TDR RW
TBI
TBYTE0
3
2
1
3
Transmissions
counter*A
counter*A
*A:Internal counter to be count transmission bytes
Generation of transmission
interrupt
interrupt
MB91520 Series
MN705-00010-1v0-E
1501