NT6881
15. Reset Source Summary
These are 5 reset sources in NT6881 as shown below.
No.
Type
Function
Description
1
Cold
Applied Externally
External Pin ( RESET )
Power-on Reset
2
3
4
5
Cold
Cold
Reset after Power-on
10 ms Reset Period
USB Reset Signaling
Resume Reset
Warm-1
Warm-2
USB Reset Period
Watch-dog Reset
Reset every 0.15S (OSC = 6MHz)
NT6881 can also be reset externally through the RESET pin. A reset is initialed when the signal at the RESET pin is held
Low for at least 10 system clocks. When RESET signal goes high, the NT6881 begins to work. The following shows the
definition of RESET input low pulse width.
V
DD
V
DD
20%VDD
20%VDD
Trstb
16. PS/2 Mouse Application
A PS/2 mouse interface is implemented in P32 (CLK), P33 (DATA) and P34 (Power Control). The timing diagrams are
described as follows.
1st
CLK
2nd
CLK
10th
CLK
11th
CLK
CLK
T4
T1A
T3
T1
T5
T2
DATA
Start Bit
Bit 0
Parity Bit
Stop Bit
Auxiliary Device Sending Data Timings
Timing
Description
MIN/MAX
u
5/25 s
T1
T1A
T2
Time from DATA transaction to falling edge of CLK 1
Time from DATA transaction to falling edge of CLK 2-11
Time from rising edge of CLK to DATA transaction
Duration of CLK inactive (LOW)
u
5/25 s
5/T4-5u s
u
30/50 s
T3
u
T4
Duration of CLK active (HIGH)
30-50 s
Time to Auxiliary Device inhibit after clock 11 to ensure the Auxiliary Device
does not start another transmission
u
>0/50 s
T5
13
ETC [ ETC ]
