Fujitsu FR81S User Manual
CHAPTER 40: MULTI-FUNCTION SERIAL INTERFACE
8. Operation of I2C
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER : MULTI-FUNCTION SERIAL INTERFACE
FUJITSU SEMICONDUCTOR CONFIDENTIAL
346
*1: If any of following conditions is met, it is necessary to set the IBCR:ACKE bit and IBCR:WSEL bit to "1" and
determine whether the device is to work as the master or slave for subsequent data.
⋅
Reserved address is a general-call address in a multi-master configuration
⋅
An arbitration lost is detected and the device may work as the slave
*2: To issue the repeat start condition when the DMA mode is enabled (SSR:DMA=1), the SSR:TBI bit is set to "1"
and the IBCR:INT bit is set to "0", follow the steps blow.
Notes:
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If the 7-bit slave address detection is enabled (ISBA:SAEN="1"), you cannot specify a 7-bit slave
address in the master mode.
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If you need to change the IBCR register during data sending or receiving, change it only when the
interrupt flag (IBCR:INT) is "1".
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If the IBCR:WSEL bit is changed, when next data of interrupt flag (IBCR:INT) and the DMA mode is
enable(SSR:DMA=1), it is used for the occurrence condition of transmission bus idle flag (SSR:TBI).
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When transmitting data is written to TDR while SSR:TDRE is "1" during transmitting data, detecting
an ACK response will activate following operations.
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When DMA mode is disabled (SSR:DMA=0), the interrupt flag (IBCR:INT) will not become "1" but
written data will be transmitted.
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When DMA mode is enabled (SSR:DMA=1), the transmission bus idle flag (SSR:TBI) will not
become "1" but written data will be transmitted.
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When transmitting data is written to TDR while SSR:TDRE is "1" during receiving data, following
operations will be activated.
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When DMA mode is disabled (SSR:DMA=0), the interrupt flag (IBCR:INT) will not become "1" but
only SSR:RDRF become "1" (when reception FIFO is enabled or number of data set in the FBYTE
register is received).
⋅
When DMA mode is enabled (SSR:DMA=1), the transmission bus idle flag (SSR:TBI) will not
become "1" but only SSR:RDRF become "1" (when reception FIFO is enabled or number of data set
in the FBYTE register is received).
MB91520 Series
MN705-00010-1v0-E
1659