Using JTAG, do I have to use TRST#?

Tip / Sign in to post questions, reply, level up, and achieve exciting badges. Know more

cross mob
u2482
Level 1
Level 1
First question asked Welcome!

Hello, I'm working on a design with CY7C4122KV13.  As per the warnings in the data sheet, the use of TRST# is not optional for this device.  I intent to use JTAG.  In the reset sequence (page 11) step 1 says we have to start out with RST# and TRST# low.  In none of the following steps does it say what you need to do with TRST#, and when.  I'm trying to keep this simple, and not have to have do something like have logic gates with reset as an input to drive TRST.  What exactly do I need to do with it?

 

0 Likes
1 Solution
Ritwick_S
Moderator
Moderator
Moderator
100 solutions authored 25 likes received 250 sign-ins

Hi @u2482 ,

 

In the datasheet, on page no. 20, it is mentioned that the TRST# input pin is used to reset the TAP controller. So, TRST# should be made low during tPWR, which is mentioned in the reset sequence section (page no. 11) and if you want to reset the TAP controller, it should be made low for at least tTSS (min 200 us).

 

Thanks,

Ritwick

View solution in original post

0 Likes
1 Reply
Ritwick_S
Moderator
Moderator
Moderator
100 solutions authored 25 likes received 250 sign-ins

Hi @u2482 ,

 

In the datasheet, on page no. 20, it is mentioned that the TRST# input pin is used to reset the TAP controller. So, TRST# should be made low during tPWR, which is mentioned in the reset sequence section (page no. 11) and if you want to reset the TAP controller, it should be made low for at least tTSS (min 200 us).

 

Thanks,

Ritwick

0 Likes