Prototype 2（用ft2232c做的jtag）

liyf

Prototype 1的改进版，用ft2232c做的jtag

My second prototype is a PCB with about 7 x 6 cm size with the followingcomponents on board:

• FT2232C with 93C56 EEPROM
  
• Step up/down regulator to guarantee 5.0 Volt from 4.5 to 5.5 USB Voltage.
  
• RS-232 Level Shifter (MAX3241)
  
• ADuM1401BRW I-Coupler for JTAG port level shifting and electrical isolation.
  
• RS-232 connector D-SUB9
  
• JTAG Connector
  
  

Be aware, the design has some flaws:

• The I-Coupler does not work at highest speed (ca. 6 MHz). It can only be  used with 3 MHz and slower. The reason is, that the couplers have a rather  large propagation delay of about 50 nsec.
  
• The I-Coupler can only be used for 3.3V and 5V targets. Future target  voltages, especially 2.5 and 1.8V are not supported.
  
• The reset signals SRST and TRST are not 3-state signals. Depending on the  schematics of the target this can cause problems.
  
  

制作资料
schematic.pdf (34.16 KB, 下载次数: 5)

2015-2-10 15:23 上传

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pcb.pdf (79.69 KB, 下载次数: 3)

2015-2-10 15:23 上传

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下载积分: 银子 -10 两