实现MAXQ2000微控制器的JTAG加载主机

文章摘要：从机评估板还在插座J3上安装了LCD子卡(MAXQ2000-K01)。表2列出了两块电路板(以及串口至JTAG电路板)的跳线和DIP开关设置。注意：应断开未列出的所有跳线。图1所示为最终设置。表2. 电路板开关和跳线设置 BoardSwitch or JumperSettingNotesSerial-to-JTAG BoardJH1Connected JH2ConnectedJH3ConnectedSupplies 5V power over JTAG cableMaster MAXQ2000 EV KitJU1Pins 1 and 2 connectedPowers VDD from 2.5

实现MAXQ2000微控制器的JTAG加载主机,标签：计算机控制技术,工厂电气控制技术,http://www.88dzw.com

从机评估板还在插座J3上安装了LCD子卡(MAXQ2000-K01)。表2列出了两块电路板(以及串口至JTAG电路板)的跳线和DIP开关设置。注意：应断开未列出的所有跳线。图1所示为最终设置。

表2. 电路板开关和跳线设置

Board	Switch or Jumper	Setting	Notes
Serial-to-JTAG Board	JH1	Connected
	JH2	Connected
	JH3	Connected	Supplies 5V power over JTAG cable
Master MAXQ2000 EV Kit	JU1	Pins 1 and 2 connected	Powers VDD from 2.5V supply
	JU2	Pins 1 and 2 connected	Powers VDDIO from 3.6V supply
	JU3	Pins 1 and 2 connected	Powers VLCD from 3.6V supply
	JU11	Connected	Powers kit board from JTAG 5V supply
	DIP SW1	Switches #4 and #8 ON; all other switches OFF	Enables serial port 0 output to J5
	DIP SW3	All switches OFF
	DIP SW6	All switches OFF
Slave MAXQ2000 EV Kit	JU1	Pins 1 and 2 connected	Powers VDD from 2.5V supply
	JU2	Pins 1 and 2 connected	Powers VDDIO from 3.6V supply
	JU3	Pins 1 and 2 connected	Powers VLCD from 3.6V supply
	DIP SW1	All switches OFF
	DIP SW3	All switches OFF
	DIP SW6	All switches OFF

图1. JTAG演示板配置

MAXQ JTAG接口

MAXQ微控制器的JTAG接口由四条信号线组成，用于测试访问端口(TAP)控制器的信息输入和输出。TAP控制器支持对MAXQ启动加载程序的访问，提供在线调试功能(注意，调试主机的实现和启动加载程序主机的实现类似，但是已经超出了本应用笔记的范围)。表3对四条JTAG信号线进行了说明。

表3. JTAG接口信号

JTAG Signal	Signal Name	Direction (Master)	Direction (Slave)	Signal Description
TMS	Test Mode Select	Output	Input	This signal line, along with the TCK line, is used to shift the TAP controller from one operational state to the next.
TCK	Test Clock	Output	Input	This signal provides the clock for the JTAG interface. The JTAG clock is limited to a maximum of the slave's clock frequency divided by 8. For example, if the slave is running at a clock frequency of 8MHz, the JTAG clock at TCK cannot run any faster than 1MHz.
TDI	Test Data In	Output	Input	This signal carries data that is sent from the master to the slave.
TDO	Test Data Out	Input	Output	This signal carries data that is sent from the slave back to the master.

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