AT80C51RD2-SLSUM Atmel, AT80C51RD2-SLSUM Datasheet - Page 33

MCU, 8BIT, 8051, 5V, SPI, 20MHZ, 44PLCC

AT80C51RD2-SLSUM

Manufacturer Part Number
AT80C51RD2-SLSUM
Description
MCU, 8BIT, 8051, 5V, SPI, 20MHZ, 44PLCC
Manufacturer
Atmel
Datasheets

Specifications of AT80C51RD2-SLSUM

Controller Family/series
(8051) 8052
No. Of I/o's
32
Ram Memory Size
1280Byte
Cpu Speed
40MHz
No. Of Timers
3
No. Of Pwm Channels
5
Core Size
8bit
Oscillator Type
External Only
Processor Series
AT80x
Core
8051
Data Bus Width
8 bit
Program Memory Type
ROMLess
Data Ram Size
1280 B
Interface Type
UART, SPI
Maximum Clock Frequency
60 MHz
Number Of Programmable I/os
32
Number Of Timers
3
Operating Supply Voltage
2.7 V to 5.5 V
Maximum Operating Temperature
+ 85 C
Mounting Style
SMD/SMT
Package / Case
PLCC
3rd Party Development Tools
PK51, CA51, A51, ULINK2
Minimum Operating Temperature
- 40 C
Cpu Family
AT80
Device Core
8051
Device Core Size
8b
Frequency (max)
40MHz
Program Memory Size
Not Required
Total Internal Ram Size
1.25KB
# I/os (max)
32
Number Of Timers - General Purpose
3
Operating Supply Voltage (typ)
3.3/5V
Operating Supply Voltage (max)
5.5V
Operating Supply Voltage (min)
2.7V
Instruction Set Architecture
CISC
Operating Temp Range
-40C to 85C
Operating Temperature Classification
Industrial
Mounting
Surface Mount
Pin Count
44
Package Type
PLCC
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Lead Free Status / RoHS Status
Lead free / RoHS Compliant

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
AT80C51RD2-SLSUM
Manufacturer:
Atmel
Quantity:
1 445
Part Number:
AT80C51RD2-SLSUM
Manufacturer:
Atmel
Quantity:
10 000
10.5
4113D–8051–01/09
PCA Watchdog Timer
Figure 10-6. PCA PWM Mode
An on-board watchdog timer is available with the PCA to improve the reliability of the system
without increasing chip count. Watchdog timers are useful for systems that are susceptible to
noise, power glitches, or electrostatic discharge. Module 4 is the only PCA module that can be
programmed as a watchdog. However, this module can still be used for other modes if the
watchdog is not needed. Figure 10-4 shows a diagram of how the watchdog works. The user
pre-loads a 16-bit value in the compare registers. Just like the other compare modes, this 16-bit
value is compared to the PCA timer value. If a match is allowed to occur, an internal reset will be
generated. This will not cause the RST pin to be driven high.
In order to hold off the reset, the user has three options:
The first two options are more reliable because the watchdog timer is never disabled as in option
#3. If the program counter ever goes astray, a match will eventually occur and cause an internal
reset. The second option is also not recommended if other PCA modules are being used.
Remember, the PCA timer is the time base for all modules; changing the time base for other
modules would not be a good idea. Thus, in most applications the first solution is the best option.
This watchdog timer won’t generate a reset out on the reset pin.
1. Periodically change the compare value so it will never match the PCA timer.
2. Periodically change the PCA timer value so it will never match the compare values.
3. Disable the watchdog by clearing the WDTE bit before a match occurs and then re-
enable it.
ECOMn
CAPPn
Enable
CAPNn MATn TOGn PWMn ECCFn
Overflow
PCA Counter/Timer
8-Bit Comparator
CCAPnH
CCAPnL
CL
CCAPMn, n= 0 to 4
0xDA to 0xDE
“1”
“0”
AT80C51RD2
CEXn
33

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