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Altera_Forum
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16 years ago

JTAG can’t find device

Hi all, I am a beginner of Altera's device. Today, When I use the JTAG mode of Quartus’ programmer to configure the device EP3C5E144, the programmer always says “Unable to scan device chain. Can...
Altera_Forum's avatar
Altera_Forum
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16 years ago

--- Quote Start ---

The Vccpd = Vccio1A = 2.5V

The program connector is powered by V_3.3

These should be the same (either V_3.3 or 2.5V).

nSTATUS and nCONFIG and CONFIG_DONE should be pulled-up to Vccpgm, which is 3.3Vcc, not V_3.3.

Maybe these are supposed to be the same, but in your schematic the labels differ.

Pull-up JTAG to Vccpd.

Pull-up other programming pins to Vccpgm.

Good luck, Ton

--- Quote End ---

Now I get Vccpgm = Vccpd = Vccio1A = 2.5V and the program connector powered by 2.5V.

nSTATUS 、nCONFIG and CONFIG_DONE are all pulled-up to Vccpgm which

is 2.5V.

However,the question still exists. when operating autodetector, both device chain and JTAG chain couldn't be scaned. It's puzzled to me that TDO still holds low level and is never changed. However, it works well in the PS mode configuration. In addition, it is nornal for the output of Bank 1A that TDI, TDO TCK and TMS belongs to.

Many thanks!Best wishes to you!