VT82C42
Key Features
- Function Description: The internal timer counting is based on an 8Mhz clock input from X1, X2 ( or X2, with X1 connected to ground)
- After the deassertion of RESET#, the VT82C42 will drive high at pin P23 and pin P27
- Otherwise, the VT82C42 will remain in AT mode
- If the VT82C42 is in AT mode after the self test, then it will drive P24 and P25 low with all other ports high
- If the VT82C42 is in PS/2 mode, then it will drive P24, P25, P22, and P27 low with all other ports high
- The VT82C42 will not change its driving value until it receives the mand "AA" from the host
