SH7760 Datasheet, PDF (1045/1345 Pages) Renesas Technology Corp – SuperHTM RISC engine

28.2 Boundary Scan TAP Controllers (EXTEST, SAMPLE/PRELOAD,
and BYPASS)
The H-UDI contains two separate TAP controllers: one for controlling the boundary-scan function
and another for controlling the H-UDI reset and interrupt functions. Assertion of TRST, for
example at power-on reset, activates the boundary-scan TAP controller and enables the boundary-
scan function prescribed in the JTAG standards. Executing a switchover command to the H-UDI
allows usage of the H-UDI reset and H-UDI interrupts. This LSI, however, has the following
limitations:
• Clock-related pins (EXTAL, XTAL, and CKIO) are out of the scope of the boundary-scan test.
• Reset-related pins (RESET, MRESET, and CA) are out of the scope of the boundary-scan test.
• H-UDI-related pins (TCK, TDI, TDO, TMS, TRST, and ASEBRK/BRKACK) are out of the
scope of the boundary-scan test.
• Analog pins (AN0 to AN3, USB_DM, and USB_DP) are out of the scope of the boundary-
scan test.
• I²C pins (I2C0_SDA, I2C0_SCL, I2C1_SDA, and I2C1_SCL) are out of the scope of the
boundary-scan test.
• To perform EXTEST, assert MRESET pin low, negate the RESET pin high and assert the CA
pin low. To perform SAMPLE/PRELOAD, assert the CA pin high and negate the RESET pin
low.
• To perform the boundary scan (EXTEST, SAMPLE/PRELOAD, or BYPASS), supply a clock
signal to the EXTAL pin and perform a power-on reset with the RESET pin. The input clock
frequency should be in the range of 1 to 34 MHz. Perform the boundary scan after the power-
on oscillation settling time (t_OSC1) has elapsed. The supply of a clock signal to the EXTAL pin
may be suspended after t_OSC1 has elapsed. For details of power-on oscillation settling time, see
section 33, Electrical Characteristics.
• During the boundary scan (EXTEST, SAMPLE/PRELOAD, and BYPASS), the maximum
TCK signal frequency is 2 MHz.
• The external controller has 3-bit access to the boundary-scan TAP controller via the H-UDI.
Table 28.2 shows the commands supported by the boundary-scan TAP controller.
Rev. 1.0, 02/03, page 995 of 1294