ATMEGA169 ATMEL [ATMEL Corporation], ATMEGA169 Datasheet - Page 288

• Manufacturer Part Number: ATMEGA169
• Description: 8-bit Microcontroller with 16K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

Reset Register
Programming Enable Register The Programming Enable Register is a 16-bit register. The contents of this register is
288
ATmega169/V
The Reset Register is a Test Data Register used to reset the part during programming. It
is required to reset the part before entering Programming mode.
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 24) after releasing the Reset Register. The out-
put from this Data Register is not latched, so the reset will take place immediately, as
shown in Figure 108 on page 234.
c o m p a r e d
0b1010_0011_0111_0000. When the contents of the register is equal to the program-
ming enable signature, programming 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 131. Programming Enable Register
t o
TDO
TDI
t h e
D
A
T
A
p r o g r a m m i n g
0xA370
=
ClockDR & PROG_ENABLE
D
e n a b l e
Q
Programming Enable
s i g n a t u r e ,
b i n a r y
2514P–AVR–07/06
c o d e