Rainbow Electronics ATmega162V - Manual (Page 204)

204
ATmega162/V
2513E–AVR–09/03
Data Registers The data registers relevant for Boundary-scan operations are:
• Bypass Register
• Device Identification Register
• Reset Register
• Boundary-scan Chain
Bypass Register The Bypass Register consists of a single Shift Register stage. When the Bypass Regis-
ter is selected as path between TDI and TDO, the register is reset to 0 when leaving the
Capture-DR controller state. The Bypass Register can be used to shorten the scan
chain on a system when the other devices are to be tested.
Device Identification Register Figure 85 shows the structure of the Device Identification Register.
Figure 85. The Format of the Device Identification Register
Version Version is a 4-bit number identifying the revision of the component. The relevant version
number is shown in Table 83.
Part Number The part number is a 16-bit code identifying the component. The JTAG Part Number for
ATmega162 is listed in Table 84.
Manufacturer ID The Manufacturer ID is a 11-bit code identifying the manufacturer. The JTAG manufac-
turer ID for ATMEL is listed in Table 85.
Reset Register The Reset Register is a test data register used to reset the part. Since the AVR tri-states
Port Pins when reset, the Reset Register can also replace the function of the unimple-
mented optional JTAG instruction HIGHZ.
A high value in the Reset Register corresponds to pulling the external Reset low. The
part is reset as long as there is a high value present in the Reset Register. Depending
MSB LSB
Bit 31 28 27 12 11 1 0
Device ID Version Part Number Manufacturer ID 1
4 bits 16 bits 11 bits 1 bit
Table 83. JTAG Version Numbers
Version JTAG Version number (Hex)
ATmega162 revision A 0x0
ATmega162 revision B 0x1
ATmega162 revision C 0x2
ATmega162 revision D 0x3
Table 84. AVR JTAG Part Number
Part number JTAG Part Number (Hex)
ATmega162 0x9404
Table 85. Manufacturer ID
Manufacturer JTAG Man. ID (Hex)
ATMEL 0x01F