IEEE 1149.1 Test Access Port Controller (JTAGC)
MPC5566 Microcontroller Reference Manual, Rev. 2
Freescale Semiconductor 24-5
24.3.2 Bypass Register
The bypass register is a single-bit shift register path selected for serial data transfer between TDI and TDO
when the BYPASS, CLAMP, HIGHZ or reserve instructions are active. After entry into the capture-DR
state, the single-bit shift register is set to a logic 0. Therefore, the first bit shifted out after selecting the
bypass register is always a logic 0.
24.3.3 Device Identification Register
The device identification register, shown in Figure 24-3, allows the part revision number, design center,
part identification number, and manufacturer identity code to be determined through the TAP. The device
identification register is selected for serial data transfer between TDI and TDO when the IDCODE
instruction is active. Entry into the capture-DR state while the device identification register is selected
loads the IDCODE into the shift register to be shifted out on TDO in the Shift-DR state. No action occurs
in the update-DR state.
24.3.4 Boundary Scan Register
The boundary scan register is connected between TDI and TDO when the EXTEST, SAMPLE or
SAMPLE/PRELOAD instructions are active. It is used to capture input pin data, force fixed values on
output pins, and select a logic value and direction for bidirectional pins. Each bit of the boundary scan
register represents a separate boundary scan register cell, as described in the IEEE 1149.1-2001 standard
and discussed in Section 24.4.5, “Boundary Scan.” The size of the boundary scan register is 480 bits.
IR[4:0]: 0_0001 (IDCODE) Access: R/O
0 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031
R PRN DC PIN MIC ID
W
Reset00001000000101100110000000011101
Figure 24-3. Device Identification Register
Table 24-2. Device Identification Register Field Descriptions
Field Description
0–3
PRN
Part revision number. Contains the revision number of the device. This field changes with each revision of the device
or module.
4–9
DC
Design center. Indicates the Freescale design center. For the MPC5566 this value is 0x20.
10–19
PIN
Part identification number. Contains the part number of the device. For the MPC5566, this value is 0x166.
20–30
MIC
Manufacturer identity code. Contains the reduced Joint Electron Device Engineering Council (JEDEC) ID for
Freescale, 0xE.
31
ID
IDCODE register ID. Identifies this register as the device identification register and not the bypass register. Always
set to 1.
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