Rainbow Electronics ATmega32L - Manual (Page 224)

224
ATmega32(L)
2503C–AVR–10/02
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 114 shows the structure of the Device Identification Register.
Figure 114. 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 87.
• Part Number
The part number is a 16-bit code identifying the component. The JTAG Part Number for
ATmega32 is listed in Table 88.
• Manufacturer ID
The Manufacturer ID is a 11 bit code identifying the manufacturer. The JTAG manufac-
turer ID for ATMEL is listed in Table 89.
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
unimplemented 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
on the Fuse settings for the clock options, the part will remain reset for a Reset Time-
Out Period (refer to “Clock Sources” on page 23) after releasing the Reset Register. The
output from this Data Register is not latched, so the reset will take place immediately, as
shown in Figure 115.
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 87. JTAG Version Numbers
Version JTAG Version Number (Hex)
ATmega32 revision A 0x0
Table 88. AVR JTAG Part Number
Part Number JTAG Part Number (Hex)
ATmega32 0x9502
Table 89. Manufacturer ID
Manufacturer JTAG Man. ID (Hex)
ATMEL 0x01F