M42800A Atmel Corporation, M42800A Datasheet - Page 56

• Manufacturer Part Number: M42800A
• Manufacturer: Atmel Corporation

Specifications of M42800A

• Flash (kbytes): 0 Kbytes
• Pin Count: 144
• Max. Operating Frequency: 33 MHz
• Cpu: ARM7TDMI
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 54
• Ext Interrupts: 54
• Usb Speed: No
• Usb Interface: No
• Spi: 2
• Uart: 2
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 8
• Self Program Memory: NO
• External Bus Interface: 1
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 3.3/5.0
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 6
• Output Compare Channels: 6
• Input Capture Channels: 6
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: No

12.2
Figure 12-4. Master Clock
12.2.1
56
Master Clock
AT91M42800A
Phase Locked Loops
Slow Clock
PLLRCA
PLLRCB
SLCK
Figure 12-2. Slow Clock
To operate correctly, the crystal must be as close to the XIN and XOUT pins as possible. An
external variable capacitor can be added to adjust the oscillator frequency.
Figure 12-3. Crystal Location
The Master Clock (MCK) is generated from the Slow Clock by means of one of the two inte-
grated PLLs and the prescaler.
Note:
Two PLLs are integrated in the AT91M42800A in order to cover a larger frequency range.
Both PLLs have a Slow Clock input and a dedicated pin (PLLRCA or PLLRCB), which must
have appropriate capacitors and resistors. The capacitors and resistors serve as a second
1. Value written at reset and not subsequently programmable.
PLLA
PLLB
MUL
MUL
GROUND
PLANE
XOUT
XIN
PLLS
C
(1)
Source
Clock
PLLCOUNT
Oscillator
32 kHz
PLL Lock Timer
CSS
SLCK
Slow Clock
Prescaler
PRES
GND
XIN
XOUT
Lock
MCK
Master Clock
1779D–ATARM–14-Apr-06