Olimex Tiny + OpenOCD + LM3S102

Hi All,

I have an LM3S102 and am looking to hook up my ARM-USB-TINY to it (2x10 standard JTAG connector). I am not sure what needs to be done in terms of pull up resistors, and inline current limiting resistors.

I have been looking at the reference designs, but they seem a little overly-complex with tri-state buffers and discrete logic components. It looks like they built in their own JTAG system. So I am wondering what the correct way to hook it up is?

Right now I have:

VREF + VTARGET ↔ 3.3V (tied directly to source)

GND ↔ GND

PB7/TRST# ↔ NTRST

PC0/TCK/SWCLK ↔ TCK

PC1/TMS/SWDIO ↔ TMS

PC2/TDI <–>TDI

PC3/TDO/SWO <–>TDO

RTCK, RST, DBGRQ, and DBGACK are floating.

In the reference designs they did not hook up TRST# to NTRST… I am not sure why. Also (I assume) I should hoot up the RST line on the micro to the RST line on the JTAG?

Should I be pulling anything high, putting resistors in series, do anything with the unused floating lines?

This JTAG stuff is a bit new and there are lots of schematics out there where things are done differently.

Thanks,

Sam

swinchen:
Hi All,

I have an LM3S102 and am looking to hook up my ARM-USB-TINY to it (2x10 standard JTAG connector). I am not sure what needs to be done in terms of pull up resistors, and inline current limiting resistors.

I have been looking at the reference designs, but they seem a little overly-complex with tri-state buffers and discrete logic components. It looks like they built in their own JTAG system. So I am wondering what the correct way to hook it up is?

Right now I have:

VREF + VTARGET ↔ 3.3V (tied directly to source)

GND ↔ GND

PB7/TRST# ↔ NTRST

PC0/TCK/SWCLK ↔ TCK

PC1/TMS/SWDIO ↔ TMS

PC2/TDI <–>TDI

PC3/TDO/SWO <–>TDO

RTCK, RST, DBGRQ, and DBGACK are floating.

In the reference designs they did not hook up TRST# to NTRST… I am not sure why. Also (I assume) I should hoot up the RST line on the micro to the RST line on the JTAG?

Should I be pulling anything high, putting resistors in series, do anything with the unused floating lines?

This JTAG stuff is a bit new and there are lots of schematics out there where things are done differently.

Thanks,

Sam

I just wired up an LM3S815, I cribbed from the Stellaris DB48 daughtercard schematic, four 10K pullups total: TRST, TCK, TMS, TDI, no pullup on TDO or SRST_B, and RTCK left unconnected.

Seems to work.