Brivo OEC 715/785/865/865 Mobile C-Arm X-Ray Product Service Manual
 
2-36 
Key allocation and make/break code 
The main control IC of the board is HT82K629A, a 
keyboard encoder. It can function both in USB and 
PS2 interface environment. What we apply in this 
design is the USB interface, and it supports the 
USB standard request as well as HID class request 
version 1.1. 
The pin assignment of HT82K629A is shown in 
Picture 4, and the pin description is shown in 
Table3 
 
Key matrix forms at the crosses between R0~R7 and C0~C19. Membrane keyboard is adopted as the external 
interface of the control board. 
Pin description of HT82K629A: