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programmers:jtag-hs2:reference-manual [2023/04/26 22:40] – added comparison chart James Colvinprogrammers:jtag-hs2:reference-manual [2023/11/09 23:35] (current) – [JTAG-HS2 Reference Manual] Arthur Brown
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-=== Download the Reference Manual === 
-  * {{ :reference:programmers:jtag-hs2:jtag-hs2_rm.pdf | PDF}} 
 ==== Features ==== ==== Features ====
  
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 The IEEE 1149.7-2009 specification requires any device that functions as a Debug and Test System (DTS) to provide a pull-up bias on the TMS and TDO pins. In order to meet this requirement, the JTAG-HS2 features weak pull-ups (100K ohm) on the TMS, TDI, TDO, and TCK signals. While not strictly required, the pull-ups on the TDI and TCK signals ensure that neither signal floats while another source is not actively driving them. The IEEE 1149.7-2009 specification requires any device that functions as a Debug and Test System (DTS) to provide a pull-up bias on the TMS and TDO pins. In order to meet this requirement, the JTAG-HS2 features weak pull-ups (100K ohm) on the TMS, TDI, TDO, and TCK signals. While not strictly required, the pull-ups on the TDI and TCK signals ensure that neither signal floats while another source is not actively driving them.
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 +{{ :programmers:jtag-hs2:jtag-input-output-stage.png?800 |}}
 +<html><center></html>//JTAG Input/Output Stage//<html></center></html>
  
 The JTAG-HS2 can interface scan chains that consist of one or more IEEE 1149-7 compatible Target Systems (TS). The devices in these chains communicate using the TMS, TDI, TDO, and TCK signals or they may communicate using only the TMS and TCK signals. Communication using only the TMS and TCK signals requires both the HS2 and TS to drive the TMS pin. The current scan format, bit period, and the level of the TCK pin determine which device is allowed to drive the TMS pin.  The JTAG-HS2 can interface scan chains that consist of one or more IEEE 1149-7 compatible Target Systems (TS). The devices in these chains communicate using the TMS, TDI, TDO, and TCK signals or they may communicate using only the TMS and TCK signals. Communication using only the TMS and TCK signals requires both the HS2 and TS to drive the TMS pin. The current scan format, bit period, and the level of the TCK pin determine which device is allowed to drive the TMS pin.