- 积分
- 66
- 在线时间
- 498 小时
- 最后登录
- 2015-5-6
- 阅读权限
- 50
- 精华
- 0
 
- UID
- 253546
- 帖子
- 199
- 精华
- 0
- 经验
- 66 点
- 金钱
- 59 ¥
- 注册时间
- 2010-10-23
|

楼主 |
发表于 2014-6-22 16:55
|
显示全部楼层
本帖最后由 sinoneptune 于 2014-6-22 17:13 编辑
另外,这个破机器的维护手册没有提供其他部分的电路板,只能自己看走线了。
只给了一个按键部分的电路图
按键部分的电路说明:
KEYIN1 through KEYIN4 and KEYOUT1 through KEYOUT6 are routed to the button board through J403 and form a button matrix. Normally, the uC holds the KEYOUT lines low and pins 59 through 62 of the uC, which correspond to the KEYIN lines, will be pulled low through R468, R469, R470 and R430. The uC has internal 80k pull downs to -20 Volts on pins 59 through 62, so the voltage there will actually be less than 0. The transistors Q400, Q402, Q403 and Q404 are used for level shifting and current gain to overcome the resistance of the carbon ink button board. When a button is pressed, a KEYOUT line will pull current through the base of the corresponding KEYIN transistor and drive one of the pins on the uC high. The uC will now begin scanning the KEYOUT lines by pulling each line individually high one at a time. This way, when the KEYIN signal disappears the uC will know the corresponding KEYOUT line and which button in the matrix is pressed. The uC can now execute the desired command.
大意是:
控制器(uC)的按键矩阵的输入脚,一般情况下电压小于零,按键矩阵的输入线是KEYIN 1~4,这四个线路上有四个三极管,用来做电流增益(因为按键是遥控器上那种胶皮石墨按键有一定的阻值),输入线是KEYOUT 1~6,按下后通过三极管给控制器的输入脚提供高电平,这时控制器开始对逐一给KEYOUT线加压,看看那个点被按下,根据按键预定的功能执行相关操作。 |
|