Hi. In the ADSP-21262 datasheet (Rev B) is it stated that the TCK line
(used for JTAG port) "must be asserted (pulsed low) after power-up or
held low for proper operation of the ADSP-21262".
However, in the ADSP-21262 EZ-KIT LITE schematic diagram it is pulled-
up to mantain a high when you just run the DSP without JTAG
intervention.
Of course the TRST* must be held down after power-up but what about the
TCK line?. It is a typo in the datasheet?
Thank you very much for any help.
Must TCK be pulled up or down in ADSP-21262?
Started by ●January 29, 2007
Reply by ●January 29, 20072007-01-29
On Fri, 26 Jan 2007, jcarlosmor wrote:
> Hi. In the ADSP-21262 datasheet (Rev B) is it stated that the TCK line
> (used for JTAG port) "must be asserted (pulsed low) after power-up or
> held low for proper operation of the ADSP-21262".
> However, in the ADSP-21262 EZ-KIT LITE schematic diagram it is pulled-
> up to mantain a high when you just run the DSP without JTAG
> intervention.
> Of course the TRST* must be held down after power-up but what about the
> TCK line?. It is a typo in the datasheet?
> Thank you very much for any help.
Sounds like a typo to me. If JTAG isn't used, the device ignores those
lines. But it may be that if you want to to use JTAG some time after
you've powered up you need to toggle TCK so the device knows that chunk of
hardware will be activated. But I bet TRST will wake that up anyway.
Patience, persistence, truth,
Dr. mike
> Hi. In the ADSP-21262 datasheet (Rev B) is it stated that the TCK line
> (used for JTAG port) "must be asserted (pulsed low) after power-up or
> held low for proper operation of the ADSP-21262".
> However, in the ADSP-21262 EZ-KIT LITE schematic diagram it is pulled-
> up to mantain a high when you just run the DSP without JTAG
> intervention.
> Of course the TRST* must be held down after power-up but what about the
> TCK line?. It is a typo in the datasheet?
> Thank you very much for any help.
Sounds like a typo to me. If JTAG isn't used, the device ignores those
lines. But it may be that if you want to to use JTAG some time after
you've powered up you need to toggle TCK so the device knows that chunk of
hardware will be activated. But I bet TRST will wake that up anyway.
Patience, persistence, truth,
Dr. mike
Reply by ●January 30, 20072007-01-30
I had alot of problems with the 21262 JTAG port. On my schematic, I
have pull-ups on the lines. However, when I don't have an emulator
connected, I put jumpers on the JTAG signals to short them to ground.
If I don't do that, sometimes the 21262 won't turn on at power-up.
The 21262 has a much more sensitive JTAG port then the 21065 did.
--- In a..., Mike Rosing wrote:
>
> On Fri, 26 Jan 2007, jcarlosmor wrote:
>
> > Hi. In the ADSP-21262 datasheet (Rev B) is it stated that the TCK line
> > (used for JTAG port) "must be asserted (pulsed low) after power-up or
> > held low for proper operation of the ADSP-21262".
> > However, in the ADSP-21262 EZ-KIT LITE schematic diagram it is pulled-
> > up to mantain a high when you just run the DSP without JTAG
> > intervention.
> > Of course the TRST* must be held down after power-up but what
about the
> > TCK line?. It is a typo in the datasheet?
> > Thank you very much for any help.
>
> Sounds like a typo to me. If JTAG isn't used, the device ignores those
> lines. But it may be that if you want to to use JTAG some time after
> you've powered up you need to toggle TCK so the device knows that
chunk of
> hardware will be activated. But I bet TRST will wake that up anyway.
>
> Patience, persistence, truth,
> Dr. mike
>
have pull-ups on the lines. However, when I don't have an emulator
connected, I put jumpers on the JTAG signals to short them to ground.
If I don't do that, sometimes the 21262 won't turn on at power-up.
The 21262 has a much more sensitive JTAG port then the 21065 did.
--- In a..., Mike Rosing wrote:
>
> On Fri, 26 Jan 2007, jcarlosmor wrote:
>
> > Hi. In the ADSP-21262 datasheet (Rev B) is it stated that the TCK line
> > (used for JTAG port) "must be asserted (pulsed low) after power-up or
> > held low for proper operation of the ADSP-21262".
> > However, in the ADSP-21262 EZ-KIT LITE schematic diagram it is pulled-
> > up to mantain a high when you just run the DSP without JTAG
> > intervention.
> > Of course the TRST* must be held down after power-up but what
about the
> > TCK line?. It is a typo in the datasheet?
> > Thank you very much for any help.
>
> Sounds like a typo to me. If JTAG isn't used, the device ignores those
> lines. But it may be that if you want to to use JTAG some time after
> you've powered up you need to toggle TCK so the device knows that
chunk of
> hardware will be activated. But I bet TRST will wake that up anyway.
>
> Patience, persistence, truth,
> Dr. mike
>
