MPC74xx (MPC7447A and MPC7448) JTAG scan chain

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MPC74xx (MPC7447A and MPC7448) JTAG scan chain

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tsi-chung_liew
NXP Employee
NXP Employee

@safwan_raad

 

I have some information on MPC74xx families (MPC7447A and MPC7448). My concern was that the particular part that the customer has is different than these. I’ve found that each part is different (even within the same families). The information I’m looking for is the bit definitions of the LSRL (which is the DR register that has all the register/ctrl/data/etc. bits in one long scan chain). From the files that I have received from Motorola/Freescale, it’s usually a bunch of definition files (.def files) that looks like they are scripts. There’s usually a sub-directory called “arrays” which has the .def files which show how to access different things such as GPR’s, memory, etc. There are also .def files which define the bit definitions/positions for certain script variables which are referenced in other .def files.

 

For example, in arrays/GPR.def (for the MPC8260), to access GPR’s the GPR address is access:

GPR_WRITE_ADDR = addr;

 

The GPR_WRITE_ADDR is defined in another file (g2h4Array.def):

GPR_WRITE_ADDR =

top_.lmu.lm7.i00.L2::

top_.lmu.lm7.i01.L2::

top_.lmu.lm7.i02.L2::

top_.lmu.lm7.i03.L2::

top_.lmu.lm7.i04.L2;

 

These top_. Bits are defined in another file (TJ1012.def):

top_.lmu.lm7.i00.L2 = long(4491:4491);

top_.lmu.lm7.i01.L2 = long(4492:4492);

top_.lmu.lm7.i02.L2 = long(4493:4493);

top_.lmu.lm7.i03.L2 = long(4494:4494);

top_.lmu.lm7.i04.L2 = long(4495:4495);

 

The long() refers to the LSRL scan chain that contains all the data/ctrl bits for JTAG debug.

 

All of the MPC internal JTAG documents are similar to this. But, some of the them also have alternative (simpler and more logical) methods of JTAG debug where there are separate IR commands for accessing different registers. For these types of chips, usually I can add support for the entire family. I found some documents for the MPC7447A and MPC7448 and those look like it might support the simpler method. But, even if it does, I’m not sure if the particular part that the customer has is compatible with the MPC7447A or the MPC7448.

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473 Views
tsi-chung_liew
NXP Employee
NXP Employee
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