JTAG circuit transferring data between devices on TMS terminals
AssigneeTexas Instruments Incorporated
InventorLee D. Whetsel
Life of this patent
Estimating the term…
Abstract
The present disclosure describes using the JTAG Tap's TMS and/or TCK terminals as general purpose serial Input/Output (I/O) Manchester coded communication terminals. The Tap's TMS and/or TCK terminal can be used as a serial I/O communication channel between; (1) an IC and an external controller, (2) between a first and second IC, or (3) between a first and second core circuit within an IC. The use of the TMS and/or TCK terminal as serial I/O channels, as described, does not effect the standardized operation of the JTAG Tap, since the TMS and/or TCK I/O operations occur while the Tap is placed in a non-active steady state.
Claims10
An electrical system comprising:
- A. first and second devices each having an IEEE 1149.1 interface including a TDI terminal, a TCK terminal, a TMS terminal, and TDO terminal, the TCK terminals of both devices being connected together and the TMS terminals of both devices being connected together;
- and
- B. circuit means in each of the first and second devices for transferring data between the two devices across the TMS terminals of both devices while a clock signal on the TCK terminals of the devices is held in a static logical state.
Dependencies are inferred from the claim text.