MicroConverter®, Multi-Channel 12-bit
a
Errata Sheet
A. This Errata sheet contains the following known bugs, anomalies and work-arounds for the ADuC831 MicroConverter
831_S01. NUMBER OF ADC CLOCKS IN PIPLINED MODE
831_S02. USE OF TIME INTERVAL COUNTER IN POWER DOWN MODE
831_S03. DAC CLEAR BIT FUNCTIONALITY
831_S04. EXTENDED (11-BIT) STACK POINTER - PUSH AND POP OPERATION
B. The Errata listed, apply to all ADuC831 packaged material branded as follows:
First Line: ADuC831XX
Fourth Line: BXX
C. Analog Devices Inc. is committed, through future silicon revisions to continuously improve silicon functionality.
Analog Devices Inc. will use its best endeavors to ensure that these future silicon revisions remain compatible with
your present software/systems that implement the recommended work-arounds outlined in this document.
ADCs and DACs with Embedded FLASH MCU
ADuC831
REV. B.1 November/2002
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
® MicroConverter is a Trademark of Analog Devices, Inc.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700 World Wide Web Site: http://www.analog.com
Fax: 781/326-8703 Analog Devices, Inc., 2002
ADuC831
831_S01. NUMBER OF ADC CLOCKS IN PIPLINED MODE
Backgound: An adc conversion takes 16 ADC clocks plus the selected acquisition
clocks.
Issue: At voltages below 3.5V in piplined mode the number of ADC clocks
required for a conversion can vary between 15 and 16 ADC clocks.
Work-Around : none.
Related Issues : This issue does not affect the performance of the ADC.
831_S02. USE OF TIME INTERVAL COUNTER IN POWER DOWN MODE
Backgound: The Time Interval Counter (TIC) can be used to time longer intervals
than the standard 8052 timers are capable of. It can be used to interrupt or
‘wake up’ the ADuC831 after a specific interval has elapsed.
There are five ways of terminating power down mode on the ADuC831.
Three of these ways namely, TIC interrupt, I2C/SPI interrupt or
INTO interrupt resume code execution at the point where it was powered
down.
Errata Sheet
Issue: When the TIC is activate (i.e. TIMECON.1 = 1)during power down a
‘wake up’ interrupt from any source may trigger a full Power-On-Reset
event instead of resuming code execution at the point where it was powered
down. This results in all SFRs being reset to their default values.
Work-Around : A bit can be set in dataflash prior to powerdown. By monitoring this bit at
the start of code execution the user can determine if the reset was due to a
‘wake up’ from powerdown.
Related Issues : This issue does not affect ‘wake up’ from powerdown if TIMECON.1=0
831_S03. DAC CLEAR BIT FUNCTIONALITY
Backgound: The DAC outputs are controlled by the SFR DACCON. The CLR1 and
CLR0 bits in DACCON can be used to force the output of DAC1 and
DAC0 to 0V.
Issue: When the DAC is enabled and in buffered mode setting the CLR1 or
CLR0 bits may cause a momentary spike on the DAC ouput before the
DAC is forced to 0V.
Work-Around : To force the output of DAC1 or DAC0 to 0V write 0000H to the
corresponding DAC data registers.
Related Issues : none.
2 of 3 REV. B.1 November/2002
ADuC831
831_S04. EXTENDED (11-BIT) STACK POINTER - PUSH AND POP OPERATION
Backgound: The ADuC831 offers an extended (11-bit) stack pointer that allows the
stack to extend into the 2 KBytes of internal XRAM. This can be very
useful where embedded functions are used.
Issue: If the extended stack pointer is enabled (CFG831.7=1) and the stack
points to the extended stack space (SPH>=1) the the PUSH direct or POP
direct instructions will not operate correctly if the direct address is less than
80H (i.e. not an SFR)
Work-Around :
Assembly Programming: By using the Accumulator the extended stack works correctly. e.g.
To PUSH:MOV A,0 To POP: POP ACC
PUSH ACC MOV 0,A
C Programming (KEIL Compier):
The KEIL Compiler only ever pushes (or pops) and SFR or any of the 32
registers (4 banks of 8 registers) onto the stack. Keil support a compiler
directive that disables absolute register addressing (#pragma NOAREGS).
Using this directive a PUSH/POP register will be automatically changed
as above.
#pragma NOAREGS
int increment(int);
Errata Sheet
void main(void)
{
int a,b,c;
a=5;
b=6;
c=increment(a)+increment(b);
while(1);
}
int increment(int a)
{
return(a+1);
}
Related Issues : none.
3 of 3 REV. B.1 November/2002
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