104
ATtiny4/5/9/10 [DATASHEET]
8127F–AVR–02/2013
14.7.1
TPIIR – Tiny Programming Interface Identification Register
Bits 7:0 – TPIIC: Tiny Programming Interface Identification Code
These bits give the identification code for the Tiny Programming Interface. The code can be used be the external
programmer to identify the TPI. The identification code of the Tiny Programming Interface is shown in
Table 14-12..14.7.2
TPIPCR – Tiny Programming Interface Physical Layer Control Register
Bits 7:3 – Res: Reserved Bits
These bits are reserved and will always read zero.
Bits 2:0 – GT[2:0]: Guard Time
These bits specify the number of additional IDLE bits that are inserted to the idle time when changing from recep-
tion mode to transmission mode. Additional delays are not inserted when changing from transmission mode to
reception.
The total idle time when changing from reception to transmission mode is Guard Time plus two IDLE bits.
Table14-13 shows the available Guard Time settings.
The default Guard Time is 128 IDLE bits. To speed up the communication, the Guard Time should be set to the
shortest safe value.
Bit
765
4321
0
Programming Interface Identification Code
TPIIR
Read/Write
RRRR
Initial Value
000
0000
0
Table 14-12. Identification Code for Tiny Programming Interface
Code
Value
Interface Identification
0x80
Bit
765
4321
0
–
GT2
GT1
GT0
TPIPCR
Read/Write
RRRR
R
R/W
Initial Value
000
0000
0
Table 14-13. Guard Time Settings
GT2
GT1
GT0
Guard Time (Number of IDLE bits)
0
+128 (default value)
00
1
+64
01
0
+32
01
1
+16
10
0
+8
10
1
+4
11
0
+2
11
1
+0