JAJSQ97J may 2009 – january 2021 XIO2001
PRODUCTION DATA
The bridge provides a programming mechanism to control serial-bus devices through system software. The programming is accomplished through a doubleword of PCI configuration space at offset B0h. Table 8-9 lists the registers that program a serial-bus device through software.
PCI OFFSET | REGISTER NAME | DESCRIPTION |
---|---|---|
B0h | Serial-bus data (see Section 8.4.56) | Contains the data byte to send on write commands or the received data byte on read commands. |
B1h | Serial-bus word address (see Section 8.4.57) | The content of this register is sent as the word address on byte writes or reads. This register is not used in the quick command protocol. Bit 7 (PROT_SEL) in the serial-bus control and status register (offset B3h, see Section 8.4.59) is set to 1b to enable the slave address to be sent. |
B2h | Serial-bus slave address (see Section 8.4.58) | Write transactions to this register initiate a serial-bus transaction. The slave device address and the R/ W command selector are programmed through this register. |
B3h | Serial-bus control and status (see Section 8.4.59) | Serial interface enable, busy, and error status are communicated through this register. In addition, the protocol-select bit (PROT_SEL) and serial-bus test bit (SBTEST) are programmed through this register. |
To access the serial EEPROM through the software interface, the following steps are performed: