|ARM Technical Support Knowledge Articles|
When using the serial JTAG vectors to test the ARM7TDMI core, the signals MCLK, TBE and nRESET need to be driven to special states, as follows:
When testing the ARM9TDMI core, only DBGEN needs to be asserted to allow debugging via the JTAG port to take place.
You must also ensure that the external system is isolated from the ARM during the serial test to remove the possibility of bi-directional signals clashing on the data bus.
The document Serial Test Procedure explains the serial test procedure in detail.
The testing of ARM's cached cores, e.g. ARM720T, ARM920T, ARM922T and ARM940T cannot be done using serialised test vectors. The reason for this is that the size of the test vectors would be prohibitively large.
Article last edited on: 2008-09-09 15:47:36
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