ADuC812 Errata Sheet
Contents
1. the incorrect baud rate Work Around Pending Related Issues All other Timer and Baud Rate generation modes operate correctly 812_S04 PORT 2 INTERNAL ACTIVE PULL UP FUNCTIONALITY Background As with standard 8051 compatible Port functionality Port 2 P2 0 P2 7 feature weak internal pull up resistors and will source current Logic 0 input current datasheet when pulled low externally On a 0 to 1 transition an additional pullup is turned on for 2 master clock periods to help increase transition speed Issue On Port 2 pins the additional pullup resistor does not come on during the required 2 clock periods when these pins are being driven as digital outputs Work Around Pending Related Issues Port 2 pins operate correctly when operating as part of the external memory interface on the device 812_S05 FLASH IEE MEMORY 3V PROGRAMMING Background The ADuC812 contains 2 separate arrays of Flash EE memory namely 8 KBytes Internal Code Space and 640 Bytes Flash EE Data Memory The 8 KBytes code space can be programmed in serial download or parallel programming modes while the 640 Byte data space can be written by user software via a specified SFR interface Issue In the temperature range 40 C to 0 C this revision of silicon will not support programming below DVpp 3V supplies Work Around In the temperature range 0 C to 85 C the device can be programmed at DVpp 3 0V 10 The device can be pr2. DMA start address is set to 000000H Related Issues None 812_S02 UART FUNCTION MULTIPROCESSOR COMMUNICATIONS MODE Background UART Modes 2 and 3 programmed via SCON have a special provision for multiprocessor communications In these modes nine data bits are received and the ninth bit goes into RB8 In this mode the port can be programmed so that when the stop bit is received the serial port interrupt is activated only if RB8 SCON 1 This feature is enabled by setting the SM2 bit in SCON Issue With SM2 set the serial port interrupt is set each time a stop bit is received regardless of the state of the RB8 bit Work Around Implement a software polling scheme in the Serial Port ISR so that the state of the RB8 bit is checked on entering the ISR If RB8 is 0 then a RETT is executed to exit the ISR immediately and only if RB8 is set will the ISR function be executed Related Issues None REV F2 FEB 02 2 of 4 ADuC812 Errata Sheet 812_S03 UART FUNCTIONALITY BAUD RATE GENERATION IN SPLIT TIMER MODE Background Timer 0 can be enabled as two 8 bit timers Mode 3 Since the overflow flag for timer 1 is used by timer 0 in split timer mode timer 1 can only be used as either a baud rate generator or as a timer as long as it does not require interrupts Issue When the timers are configured as above with timer 1 as a baud rate generator the reload value in TH1 fails to be loaded into THO generating
3. These recommendations can be found in the ADuC812 technical datasheet REVA and the ADuC812 User s Manual Draft 0 5 available at http www analog com microconverter 812_S08 RESET FUNCTIONALITY WHEN EXECUTING FROM EXTERNAL MEMORY ONLY Background The ADuC812 can be reset using in three ways namely a Power cycling the part b Toggling the reset pin and c A watchdog Timeout Issue a When executing from external memory only i e EA tied low resetting the ADuC812 by toggling the RESET pin can cause the part to enter an internal emulation mode b When executing from external memory only i e EA tied low a watchdog reset can cause the part to enter an internal emulation mode Work Around a A subsequent toggle of the reset pin will reset the part b Tying the PSEN pin low through an external pull down resistor maximum value 4KOhm prevents entry to the emulation mode and correctly resets the ADuC812 Related Issues a This issue does not occur when executing code from internal memory only b This issue does not occur when executing code from both internal and external code memory c This issue does not occur when power cycling the ADuC812 REV E2 FEB 02 4 of 4
4. ANALOG MicroConverter Multi Channel 12 bit DEVICES ADC with Embedded FLASH MCU Errata Sheet ADuC812 A This Errata sheet represents the known bugs anomalies and work arounds for the ADuC812 MicroConverter B The Errata listed apply to all ADuC812 packaged material branded as follows Production Material ADUC812BS Date Stamp AD Logo C Lot Number Note The indentifier C after the ADLogo on the second line of the brand C Errata Sheets referring to previous silicon revisions are available on our web site at http www analog com microconverter erratasheets html D Because of silicon revisions and improved work arounds this Errata Sheet will be updated periodically Please find the latest Errata Sheet listed on the World Wide Web at http www analog com microconverter erratasheets html E 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 REV F2 FEB 02 Information furnished by Analog Devices is believed to be accurate and MicroConverter is a Trademark of Analog Devices Inc reliable However no responsibility is assumed by Analog Devices for its use nor for any infringements of patents or other rights of third parties One
5. Technology Way P O Box 9106 Norwood MA 02062 9106 U S A which may result from its use No license is granted by implication or Tel 781 329 4700 World Wide Web Site http www analog com otherwise under any patent or patent rights of Analog Devices Fax 781 326 8703 Analog Devices Inc 2000 ADuC812 Errata Sheet 812_S01 ADC FUNCTION ADC CONVERSION IN DMA MODE Background The ADC can be triggered by 1 of 4 trigger events in Normal and DMA operating modes namely Single Software Conversion Continuous Software Conversions External Pin Triggered Conversions and Timer2 triggered Conversions DMA mode is initiated by setting the DMA bit in the ADCCON2 SFR and the DMA controller proceeds starting from the external data memory address indicated by the DMA address SFRs DMAL H P Once a DMA conversion sequence is complete both the DMA bit and the bit controlling the conversion mode are reset by the DMA controller Issue A DMA operation will not execute when triggered from Timer2 driven conversions unless when configuring the ADC ADCCON2 is written prior to ADCCONI Work Around A For Timer2 triggered DMA conversions ensure that the correct configuration sequence is used for the ADC i e configure ADCCON2 then ADCCONI1 Issue B DMA operation will not execute when triggered from Timer2 driven conversions unless DMA Address DMAL H P is initially set to 000000H Work Around B For Timer2 triggered DMA conversions ensure that the
6. ogrammed at DVpp 3 3V 10 over the full temperature range 40 C to 85 C Related Issues The device can be programmed at DVpp 5V 10 over the full temperature range 40 C to 85 C REV F2 FEB 02 3 of 4 ADuC812 Errata Sheet 812_S06 FUNCTIONALITY OF PSMCON 1 BIT IN THE PSMCON SFR Background The PSMCON 1 bit in the PSMCON SER can be used to indicate which supply caused the active power supply trip condition PSMCON 1 0 indicates a DVpp fault while PSMCON 1 1 indicates an AVpp fault Issue If the power supply trip point selection bits are set to select the 4 63V or 4 37V supply trip points the PSMCON 1 AVpp DVpp power supply trip indicator bit may not correctly indicate which supply has caused the fault The supply trip indicator bit will function correctly at all other trip point voltage levels Work Around Pending Related Issues It should be noted that while the trip indicator bit function is suspect at these trip levels the PSM function itself is still 100 operational even at 4 63V and 4 37V trip levels generating an interrupt as soon as any one of the supply pins falls below the specified supply voltage trip point selection 812_S07 EXTERNAL POWER ON RESET POR OPERATION DOCUMENTATION UPDATE All ADuC812 documentation has been updated to include a detailed recommendation on how the external RESET pin 15 should be driven with external POR circuitry during power on power down and brown out conditions
Download Pdf Manuals
Related Search