Renesas R5S72621 Manual Do Utilizador

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Section 21   IEBus
TM
 Controller 
R01UH0134EJ0400  Rev. 4.00  
 
Page 1095 of 2108 
Sep 24, 2014 
 
 
 
SH7262 Group, SH7264 Group 
(b)  Acknowledge bit at the End of the Control Field 
The acknowledge bit at the end of the control field becomes NAK in the following cases and 
transfer is stopped. 
  When the parity of the control bits is incorrect 
  When the bit 3 of the control bits is 1 (data write) although the slave receive buffer* is not 
empty 
  When the control bits are set to data read (H'3, H'7) although the slave transmit buffer* is 
empty 
  When another unit which locked the slave unit requests H'3, H'6, H'7, H'A, H'B, H'E, or H'F in 
the control bits although the slave unit has been locked 
  When the control bits are the locked address read (H'4, H'5) although the unit is not locked 
  When a timing error occurs 
  When the control bits are undefined 
 
Note:  See section 21.1.3 (1), Slave Status Read (Control Bits: H'0, H'6). 
(c)  Acknowledge Bit at the End of the Message Length Field 
The acknowledge bit at the end of the message length field becomes NAK in the following cases 
and transfer is stopped. 
  When the parity of the message length bits is incorrect 
  When a timing error occurs 
 
(d)  Acknowledge Bit at the End of the Data Field 
The acknowledge bit at the end of the data field becomes NAK in the following cases and transfer 
is stopped. 
  When the parity of the data bits is incorrect* 
  When a timing error occurs after the previous transfer of the acknowledge bit 
  When the receive buffer becomes full and cannot accept further data* 
 
Note:  *  In this case, the data field is transferred repeatedly until the number of data reaches the 
maximum number of transfer bytes if the number of data does not exceed the 
maximum number of transfer bytes in one frame.