Lpc2000

The real Wiggler has host control of the TRST. Even if the TAP
controller can be reset by a TCK sequence, wouldn't the Macraigor
OCDremote software likely implement support for reseting the TAP
controller only through the TRST signal and omit support for doing a
special TCK reset sequence? I wonder if this could explain why people
say that they have trouble with OCDremote while the OpenOCD software
works better. Does OpenOCD support the special TCK sequence for
reseting the TAP controller?

In other news, I'm starting to read up on the RTCK pin. The LPC2103
preliminary user's manual, section 20.5 says:

"On the LPC2101/02/03, the pins TMS, TCK, TDI, TDO, and TRST are
multiplexed with P0.27 - P0.31. To have them come up as a Debug port,
connect a weak bias resistor (4.7-10 k\u03a9 depending on the external JTAG
circuitry) between VSS and the RTCK pin. To have them come up as GPIO
pins, do not connect a bias resistor, and ensure that any external
driver connected to Pin 26 (RTCK) is either driving high or is in
high-impedance state during Reset."

This seems to be in contradiction with section 20.8.2, which says:

"The Primary JTAG port can be selected for debugging only when DBGSEL
and RTCK pins are HIGH at reset (see Figure 66). If at least one of
the DBGSEL or RTCK lines is LOW at reset, JTAG will not be enabled and
can not be used for later debugging."

Should RTCK be pulled high or pulled low to enable the JTAG debugger pins?

--- In lpc2000@yahoogroups.com, "ntfreak2000" <ntfreak2@h...> wrote:

> The TSRT pin is optional, the jtag cell reset can be obtained by a TCK
> sequence. Anyway most of the manufactursr eg, philips. ST reset this
> when the SRST pin is asserted.
> 
> This is what causes the problem of setting a hardware breakpoint at 0
> and doing a hard reset - does not work for a lot of devices.
> 
> For some reason ARM9 devices very rarely reset the cell when SRST is
> asserted.
> 
> TRST would normally be pulled up to enable debugging.