AT91M55800A-33CJ Atmel, AT91M55800A-33CJ Datasheet - Page 90

• Manufacturer Part Number: AT91M55800A-33CJ
• Description: IC ARM MCU 16BIT 176BGA
• Manufacturer: Atmel
• Series: AT91SAMr

Specifications of AT91M55800A-33CJ

• Core Processor: ARM7
• Core Size: 16/32-Bit
• Speed: 33MHz
• Connectivity: EBI/EMI, SPI, UART/USART
• Peripherals: POR, WDT
• Number Of I /o: 58
• Program Memory Type: ROMless
• Ram Size: 8K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.6 V
• Data Converters: A/D 8x10b; D/A 2x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 176-LFBGA
• Processor Series: AT91Mx
• Core: ARM7TDMI
• Data Bus Width: 32 bit
• Data Ram Size: 8 KB
• Interface Type: EBI, SPI, USART
• Maximum Clock Frequency: 33 MHz
• Number Of Programmable I/os: 58
• Number Of Timers: 10 bit
• Operating Supply Voltage: 3 V to 3.6 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: JTRACE-ARM-2M, MDK-ARM, RL-ARM, ULINK2
• Development Tools By Supplier: AT91EB55
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit, 8 Channel
• On-chip Dac: 8 bit, 2 Channel
• Cpu Family: AT91
• Device Core: ARM7TDMI
• Device Core Size: 32b
• Frequency (max): 33MHz
• Program Memory Size: Not Required
• Total Internal Ram Size: 8KB
• # I/os (max): 58
• Number Of Timers - General Purpose: 6
• Operating Supply Voltage (typ): 3.3V
• Operating Supply Voltage (max): 3.6V
• Operating Supply Voltage (min): 2.7V
• Instruction Set Architecture: RISC
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 176
• Package Type: BGA
• For Use With: AT91EB55 - KIT EVAL FOR ARM AT91M55800A
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Program Memory Size: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

14. WD: Watchdog Timer
Figure 14-1. Watchdog Timer Block Diagram
90
AT91M5880A
MCK/1024
MCK/4096
MCK/128
MCK/32
WD_RESET
Advanced
Bus (APB)
Peripheral
WDIRQ
The AT91M55800A has an internal Watchdog Timer that can be used to prevent system lock-up
if the software becomes trapped in a deadlock.
In normal operation the user reloads the watchdog at regular intervals before the timer overflow
occurs. If an overflow does occur, the watchdog timer generates one or a combination of the fol-
lowing signals, depending on the parameters in WD_OMR (Overflow Mode Register):
The watchdog timer has a 16-bit down counter. Bits 12 - 15 of the value loaded when the watch-
dog is restarted are programmable using the HPVC parameter in WD_CMR (Clock Mode). Four
clock sources are available to the watchdog counter: MCK/32, MCK/128, MCK/1024 or
MCK/4096. The selection is made using the WDCLKS parameter in WD_CMR. This provides a
programmable time-out period of 4 ms to 8 sec. with a 33 MHz system clock.
All write accesses are protected by control access keys to help prevent corruption of the watch-
dog should an error condition occur. To update the contents of the mode and control registers it
is necessary to write the correct bit pattern to the control access key bits at the same time as the
control bits are written (the same write access).
• If RSTEN is set, an internal reset is generated (WD_RESET as shown in Figure 14-1).
• If IRQEN is set, a pulse is generated on the signal WDIRQ which is connected to the
• If EXTEN is set, a low level is driven on the NWDOVF signal for a duration of 8 MCK cycles.
Advanced Interrupt Controller
Clock Select
Control Logic
CLK_CNT
Clear
Overflow
Programmable
Down Counter
16-Bit
NWDOVF
1745F–ATARM–06-Sep-07