NS7520B-1-I46 Digi International, NS7520B-1-I46 Datasheet - Page 66

• Manufacturer Part Number: NS7520B-1-I46
• Description: IC ARM MICROPROCESSOR 177BGA
• Manufacturer: Digi International
• Series: NET+ARM®r

Specifications of NS7520B-1-I46

• Applications: Network Processor
• Core Processor: ARM7
• Program Memory Type: External Program Memory
• Controller Series: -
• Ram Size: External
• Interface: EBI/EMI, Ethernet, DMA, SPI, UART
• Number Of I /o: 16
• Voltage - Supply: 1.4 V ~ 3.6 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 177-LFBGA
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

PLL Settings register: Setting the PLL frequency on bootup
5 4
S e t t i n g t h e P L L f r e q u e n c y
Setting the PLL frequency
Three fields — IS (charge pump current), FS (output divider), and ND (PLL
multiplier) — in the PLL Settings register control the behavior of the PLL circuit. You
cannot write to the PLL Settings register directly, however; it is configured in one of
these ways:
1
2
The PLL Settings register, FFB0 0040, is initialized at bootup by reading address lines
A[8:0]. Only the ND field can be changed by writing a new bus speed to the PLLCNT
register in the PLL Control register.
Table 21: PLL Settings register bit definition
D31:09
Bits
15
31
On bootup, the PLL Settings register is configured by reading the values on
address lines A[8:0]. The address lines have internal pullups. The normally high
values can be changed to 0 by connecting 2.7K pulldown resistors.
The PLL Settings register is configured by writing to the PLL Control register.
Only the ND field can be reconfigured this way.
30
14
N/A
Access
N S 7 5 2 0 H a r d w a r e R e f e r e n c e , R e v G 9 / 2 0 0 7
29
13
Reserved
28
12
Reserved
Mnemonic
27
11
26
10
N/
Reset
25
9
24
8
Reserved
IS
N/A
Description
23
7
22
6
FS
21
5
20
4
19
3
ND
18
2
17
1
16
0