6.3 Transfer Data (XferData) Pseudo Operation

Format:
oData = XferData (iData)
Purpose:
  • To clock data to and from the register selected by the command.
Description (in sequence):
  1. The TMS Header is clocked into the device to select the Shift DR state.
  2. The data is clocked in/out of the device on TDI/TDO while holding signal TMS low.
  3. The last MSb of the data is clocked in/out while setting TMS high.
  4. The TMS Footer is clocked in on TMS to return the TAP controller to the Run/Test Idle state.
Restrictions:
  • None.
Example:
  • The following is an example of how to use the Transfer Data (XferData) function:
    oData = XferData (32’h0x12)
Figure 6-5. Transfer Data (XferData) Four-Wire
Figure 6-6. Transfer Data (XferData) Two-Wire (4-phase)