8.3.2. Pull-up resistors

The IEEE 1149.1 standard effectively requires TDI and TMS to have internal pull-up resistors. In order to minimize static current draw, these resistors are not fitted to the ARM9E-S core. Accordingly, the four inputs to the test interface (the TDO, TDI, and TMS signals plus TCK) must all be driven to valid logic levels to achieve normal circuit operation.

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