Intel N2820 FH8065301616603 Data Sheet
Product codes
FH8065301616603
Datasheet
1239
PCU – iLB – 8254 Timers
27
PCU – iLB – 8254 Timers
The 8254 contains three counters which have fixed uses including system timer and
speaker tone. All registers are clocked by a 14.31818 MHz clock.
speaker tone. All registers are clocked by a 14.31818 MHz clock.
27.1
Signal Descriptions
See
for additional details.
The signal description table has the following headings:
•
Signal Name: The name of the signal/pin
•
Direction: The buffer direction can be either input, output, or I/O (bidirectional)
•
Type: The buffer type found in
•
Description: A brief explanation of the signal’s function
27.2
Features
27.2.1
Counter 0, System Timer
This counter functions as the system timer by controlling the state of IRQ0 and is
programmed for Mode 3 operation. The counter produces a square wave with a period
equal to the product of the counter period (838 ns) and the initial count value. The
counter loads the initial count value one counter period after software writes the count
programmed for Mode 3 operation. The counter produces a square wave with a period
equal to the product of the counter period (838 ns) and the initial count value. The
counter loads the initial count value one counter period after software writes the count
I
O
I
O
I
O
I
O
I
O
I
O
I
O
O
Platform Control Unit
UART
LP
C
GP
IO
IO
RT
C
C
HP
ET
ET
82
59
59
AP
IC
IC
82
54
54
SMB
iLB
SPI
PM
C
C
Table 186. 8254 Signals
Signal Name
Direction/
Type
Description
ILB_8254_SPKR
O
TBD
Speaker: The signal drives an external speaker driver device, which in
turn drives the system speaker. Upon PMC_PLTRST#, its output state is
0.
This signal is multiplexed and may be used by other functions.
This signal is multiplexed and may be used by other functions.