M42800A Atmel Corporation, M42800A Datasheet - Page 17

• 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

8.3
8.4
8.4.1
8.4.2
8.4.3
1779ES–ATARM–14-Apr-06
Peripheral Data Controller
System Peripherals
PMC: Power Management Controller
ST: System Timer
AIC: Advanced Interrupt Controller
The AT91M42800A has an 8-channel PDC dedicated to the two on-chip USARTs and to the two
on-chip SPIs. One PDC channel is connected to the receiving channel and one to the transmit-
ting channel of each peripheral.
The user interface of a PDC channel is integrated in the memory space of each USART channel
and in the memory space of each SPI. It contains a 32-bit address pointer register and a 16-bit
count register. When the programmed data is transferred, an end-of-transfer interrupt is gener-
ated by the corresponding peripheral. See the USART section and the SPI sections for more
details on PDC operation and programming.
The AT91M42800A’s Power Management Controller optimizes the power consumption of the
device. The PMC controls the clocking elements such as the oscillator and the PLLs, and the
System and the Peripheral Clocks. It also controls the MCKO pin and permits to the user to
select four different signals to be driven on this pin.
The AT91M42800A has the following clock elements:
The on-chip low-power oscillator together with the PLL-based frequency multiplier and the pres-
caler results in a programmable clock between 500 Hz and 66 MHz. It is the responsibility of the
user to make sure that the PMC programming does not result in a clock over the acceptable
limits.
The System Timer module integrates three different free-running timers:
These timers count using the Slow Clock provided by the MCU. Typically, this clock has a fre-
quency of 32768 Hz.
The AT91M42800A has an 8-level priority, individually maskable, vectored interrupt controller.
This feature substantially reduces the software and real-time overhead in handling internal and
external interrupts.
• The oscillator providing a clock that depends on the crystal fundamental frequency
• PLL A providing a low-to-middle frequency clock range
• PLL B providing a middle-to-high frequency range
• The Clock prescaler
• The ARM Processor Clock controller
• The Peripheral Clock controller
• The Master Clock Output controller
• A Period Interval Timer setting the base time for an Operating System.
• A Watchdog Timer that is built around a 16-bit counter, and is used to prevent system lock-up
• A Real-time Timer counting elapsed seconds.
connected between the XIN and XOUT pins
if the software becomes trapped in a deadlock. It can generate an internal reset or interrupt,
or assert an active level on the dedicated pin NWDOVF.
AT91M42800A
17