AT89C5131A-L Atmel Corporation, AT89C5131A-L Datasheet - Page 15

• Manufacturer Part Number: AT89C5131A-L
• Manufacturer: Atmel Corporation

Specifications of AT89C5131A-L

• Flash (kbytes): 32 Kbytes
• Max. Operating Frequency: 48 MHz
• Cpu: 8051-12C
• Max I/o Pins: 34
• Usb Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 1
• Twi (i2c): 1
• Uart: 1
• Sram (kbytes): 1.25
• Eeprom (bytes): 1024
• Self Program Memory: API
• Operating Voltage (vcc): 3.0 to 3.6
• Timers: 4
• Isp: UART/USB
• Watchdog: Yes

PLL Programming
Divider Values
4338F–USB–08/07
The PLL is programmed using the flow shown in Figure 11. As soon as clock generation
is enabled user must wait until the lock indicator is set to ensure the clock output is
stable.
Figure 11. PLL Programming Flow
To generate a 48 MHz clock using the PLL, the divider values have to be configured fol-
lowing the oscillator frequency. The typical divider values are shown in Table 13.
Table 13. Typical Divider Values
Oscillator Frequency
12 MHz
16 MHz
18 MHz
20 MHz
24 MHz
32 MHz
40 MHz
3 MHz
6 MHz
8 MHz
R+1
Configure Dividers
16
12
12
Programming
8
6
4
3
8
2
3
PLL Locked?
N3:0 = xxxxb
R3:0 = xxxxb
LOCK = 1?
Enable PLL
PLLEN = 1
PLL
N+1
10
1
1
1
1
1
3
5
1
2
PLLDIV
F0h
B4h
B9h
70h
50h
30h
20h
72h
10h
21h
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