Appendix
26
EC41812CLDNA
(4)
Enable/Disable
WDT
a.
Enable WDT:
outportb(0x66, TIME_OUT_VALUE); /*Please use the
overtime unit (0x01~0xFF) to replace the constant TIME_OUT_VALUE*/
b.
Exit WDT:
outportb(0x66, 0x00);
Digital IO Programming Guide
The board educes out 8 pins via one PCA 9534 chip, which could set its input and
output via programming. The necessary constant parameters and registers in use
describe SMBUS I/O space base address: BAR=0x400
First PCA9534 address slave_adr=0x20;
the high 7bit of the 8bit address
bit[7:1] is the hardware setup address
0x20, while the last bit is used to set
the read and write function, bit[0]=0,
write; bit[0]=1, read;
0x40:
address and write command, used to
modify the value of GPIO controlling
register;
0x41:
address and read command, used to
read the value of GPIO controlling
register;
4 GPIO controlling registers
0x00input port (Read), when bit7~bit0 is 1, its corresponding pin is high level; when
bit7~bit0 is 0, it is low level.