DS3170 Maxim Integrated Products, DS3170 Datasheet - Page 67

• Manufacturer Part Number: DS3170
• Description: Network Controller & Processor ICs DS3-E3 Single-Chip T ransceiver T3-E3 Fra
• Manufacturer: Maxim Integrated Products

Table 10-12. Global 8 kHz Reference Source Table
Table 10-13
Table 10-13. Port 8 kHz Reference Source Table
Figure 10-6 shows the 8 kHz reference logic tree.
Figure 10-6. 8KREF Logic
10.4.3 One Second Reference Generation
The one second reference signal is used as an option to update the performance registers on a precise one
second interval. The generated internal signal should be about 50% duty cycle and it is derived from the Global 8
kHz reference signal by dividing it by 8000. The low to high edge on this signal will set the GL.SRL.ONESL latched
one second detect bit which can generate an interrupt when the GL.SRIE.ONESIE interrupt enable bit is set. The
low to high edge can also be used to generate performance monitor updates when GL.CR1.GPM[1:0]=1X.
GL.CR2.
PORT.CR3.
G8KIS
0
0
0
0
1
0X
10
11
G8KRS[1:0]
lists the selectable sources for port 8 kHz reference sources.
P8KRS[1:0]
GL.CR2.
XX
00
01
10
11
FRAME MODE
FRAME MODE
RX CLOCK
FROM CLAD
TX CLOCK
None, the 8KHZ divider is disabled.
Derived from CLAD output clock
8KREF source selected by P8KRS[1:0]
Undefined
GPIO4
Undefined
Internal receive framer clock
Internal transmit framer clock
DS3 CLK
P8KRS
E3 CLK
GPIO4
SOURCE
SOURCE
CLOCK DIVIDER
67 of 230
CLOCK DIVIDER
G8KRS
DS3170 DS3/E3 Single-Chip Transceiver
G8KIS
GLOBAL 8KREF
PORT 8KREF