27.5.13 Slave Data

Name: SDATA
Offset: 0x0D
Reset: 0x00
Property: -

Bit 76543210 
 DATA[7:0] 
Access R/WR/WR/WR/WR/WR/WR/WR/W 
Reset 00000000 

Bits 7:0 – DATA[7:0] Data

The Slave Data register I/O location (DATA) provides direct access to the slave's physical Shift register, which is used both to shift data out onto the bus (transmit) and to shift in data received from the bus (receive). The direct access implies that the Data register cannot be accessed during byte transmissions. Built-in logic prevents any write accesses to the Data register during the shift operations. Reading valid data or writing data to be transmitted can only be successfully done when the bus clock (SCL) is held low by the slave (i.e., when the slave CLKHOLD bit is set). However, it is not necessary to check the CLKHOLD bit in software before accessing the slave DATA register if the software keeps track of the present protocol state by using interrupts or observing the interrupt flags. Accessing the slave DATA register, assumed that clock hold is active, auto-trigger bus operations dependent of the state of the Slave Acknowledge Action Command bits (ACKACT) and type of register access (read or write).