Adaptec 1737100 Programmer Manual - Page 108

AIC-6915 Ethernet LAN Controller Programmer's Manual GPIO Register Type: R/W Internal Registers Subgroup: Ethernet Functional Registers Byte Address: 8C - 8Fh The GPIO register provides for host software control of the GPIO[3:0] pins. Bit(s) 31:28 27:24 23:20 19:16 15:8 7:4 3:0 Table 7-45. GPIO Register Reset rw Value Description/Function r 0 Reserved: Always written as '0'. r/w 1111 GPIOCtrl[3:0]: If any of these bits are set, the corresponding GPIO bit is configured as an input. Otherwise it is an output. r 0 Reserved: Always written as '0'. r/w 0 GPIOOutMode[3:0]: Active only when the corresponding GPIO pin is configured as an output. Bit 0 controls GPIO[0], bit 1 controls GPIO[1], etc. '0' - Regular output. '1' - Open Drain output. r/w 0 GPIOInpMode[7:0]: Active only when the corresponding GPIO pin is configured as an input. Bits [1:0] control GPIO[0], Bits[3:2] control GPIO[1] etc. '00' - Regular input. '01' - Corresponding interrupt status bit is set when the GPIO input is high. '10' - Corresponding interrupt status bit is set when the GPIO input is low. '11' - Corresponding interrupt status bit is set when the GPIO input is changing. r 0 Reserved: Always reads 0. r/w depends GPIOData[3:0]: Reading the port gives the value on the on input GPIO[3:0] pins. Writing the port is effective only for those GPIO value pins configured as outputs. In this case the written value is driven to the output. 7-36