Rainbow Electronics ATmega32L - Manual (Page 275)

275
ATmega32(L)
2503C–AVR–10/02
Programming Enable Register The Programming Enable Register is a 16-bit register. The contents of this register is
compared to the programming enable signature, binary code 1010_0011_0111_0000.
When the contents of the register is equal to the programming enable signature, pro-
gramming via the JTAG port is enabled. The register is reset to 0 on Power-on Reset,
and should always be reset when leaving Programming mode.
Figure 139. Programming Enable Register
Programming Command
Register The Programming Command Register is a 15-bit register. This register is used to seri-
ally shift in programming commands, and to serially shift out the result of the previous
command, if any. The JTAG Programming Instruction Set is shown in Table 117. The
state sequence when shifting in the programming commands is illustrated in Figure 141.
Figure 140. Programming Command Register
TDI
TDO
D
A
T
A
=
D Q
ClockDR & PROG_ENABLE
Programming Enable
$A370
TDI
TDO
S
T
R
O
B
E
S
A
D
D
R
E
S
S
/
D
A
T
A
Flash
EEPROM
Fuses
Lock Bits