DOWNLOADER AND RT-MONITOR ------------------------- CONTENTS: - Copyright and Usage Terms - Introduction - Practical Issues - Monitor/Downloader Usage - RT-Monitor Commands - Downloader - Baud Rate Calculation - Error Flag Bits - Changes in version 2 **************************************************************** COPYRIGHT AND USAGE TERMS Copyright (c) B Knudsen Data 1999-2002, Trondheim - Norway. This code can be used FREE for all kinds of testing and debugging of PICmicro programs. This also includes permission to modify and extend the source code for the purpose of such testing and debugging. Permanently including the binary code in a commercial product requires a license of the CC5X compiler. Resale and redistribution of the possibly modified monitor source code will require written permission from B Knudsen Data. B Knudsen Data assumes no responsibility for errors or defects in the software or in the documentation supplied. Any use of this software implies the acceptance of this condition. **************************************************************** INTRODUCTION: Developed for use on the PIC16F870/871/873/874/876/877 and the PIC16F873A/874A/876A/877A devices. Can be adapted to other PICmicro flash devices. The code has been strongly optimized for size and low memory usage. Also the call level usage is kept low to enable calls from the application program. NOTE that the 16F87XA needs in general around 100 more code words than the 16F87X, and use a few more RAM locations. * general features: * terminal ASCII interface * accepts CR or LF or both for line termination * starts on device reset and/or can be called from user program * only around 650 code words (52 byte RAM) for ALL features * including 50 words for (minimal) help info * 580 code words (49 byte RAM) for Downloader & RT-monitor * requires 3 stack levels (can be reduced to 2) * rt-monitor features: * size: 408 code words (standalone), RAM around 22 bytes * display and change RAM, PROGRAM code and EEPROM memory * uses hexadecimal numbers only * downloader features: * size: 434 code words (standalone), RAM around 43 bytes * automatic downloading (no command required) * detects ':' and turns off echo * automatic program start after programming (eof-record) * downloads ASCII file, INTEL HEX FORMAT (INHX8M) * INHX32 is optional * skips programming of program memory words that are unchanged * program EEPROM data * address 0x2100-0x217F/0x21FF * comprehensive error detection * detects many kinds of errors that may occur during downloading * test program word after writing * set error flag if location was not programmed correctly * uses XOFF and XON to stop data stream while programming * enables long distance (modem) programming by using a buffer * avoid data for device fuse registers (0x2007) * protection on overwriting downloader code **************************************************************** PRACTICAL ISSUES: Communication: The monitor/downloader use the USART for communication with the external world. RC6/TX pin : output serial data from PICmicro device RC7/RC pin : input serial data to PICmicro device Note that the signal levels needs to be adapted to a standard, i.e., RS-232 or RS422. How to do this is not described in this documentation. The serial data format is (unless changed in the source code): * one start bit * 8 data bits, bit 0 first * one stop bit * baud rate is selectable by changing 'monitor.h' WRT: Flash Program Memory Write Enable The WRT bit need to be set to 1 to enable FLASH programming from application/downloader program. WRT: bit 9 of the Configuration Word (address 0x2007). More documentation is found by reading section 'Special Features' of the Microchip PDF manual for the particular device. NOTE that the Configuration word (0x2007) can NOT be reprogrammed from the downloader/monitor! Interrupt: The monitor/downloader does not use interrupt. The user application may contain an interrupt routine if needed. However, if interrupts need to be enabled when entering the monitor, some monitor source modification may be required. Just search for GIE in 'monitor.c' and change the code as required. Just remember that interrupt must be DISABLED during FLASH/EEPROM programming, and also that USART interrupt must be disabled until the monitor exits. In file 'monitor.h' there is a macro 'RESTORE_GIE' which should be defined if GIE should be restored on return from the monitor. This is useful only when RTMONITOR is defined. Monitor activation: DEMO.c : demo application that includes the loader/monitor code DEMO1.c : demo application to be loaded using the loader/monitor DEMO2.c : demo application with hardcoded breakpoints and testpoints Program 'demo.c' show how to embed the monitor/downloader into an user program. By defining: #define START_MONITOR_ON_RESET the monitor/downloader will be started instead of the application. The startup sequence is found in 'rtmon.h'. NOTE: START_MONITOR_ON_RESET must be used consistently, i.e. not changed on later compilations/downloads. It is possible to add code that will test the state of an input pin, and starting the application or the monitor depending on the state of this pin. This code can be inserted both in routine monitor(); or in the user application. Note that RTMONITOR need to be defined in order the get a RETURN when routine monitor(0) finishes. If RTMONITOR is not defined, a restart will occur. Using monitor(1) will always give a restart. Features enabled: defined in 'monitor.h' The start address of the monitor/downloader utility can be adjusted (file 'rtmon.h') according to the features enabled. No user program can exceed the LOADER_START address. **************************************************************** MONITOR/DOWNLOADER USAGE: 1. The monitor can be started in the user program, for example after checking an input pin in the initialization sequence or in the main program loop. Note that 3 stack levels must be available. The start-vector is normally set to address 0 (no call to the monitor at startup). The monitor will use some RAM (at high addresses) for temporary storage. The application can use this RAM between calls to the monitor. 2. An optional way of activating the monitor/downloader is to start it at device reset. This is done by inserting: #define START_MONITOR_ON_RESET before the #include "rtmon.h" statement. Assembly users should add similar code as shown in this file at address 0-2 and put the start-vector at address 3. That is all. User code can not overwrite the downloader code (protected). All RAM memory can be used in the application. The use of the downloader can be redefined at each program download. The restriction is that the reserved downloader code area can not be programmed, and the application resetVector must not be changed. The monitor/downloader RAM area can be used in the application code. Note that these location can change when using calls to the monitor. 3. The RT-monitor can included in non-flash devices also. Some editing is required to remove the programming feature. The available features will be inspect/change RAM, execute function, application supported breakpoints and testpoints. **************************************************************** RT-MONITOR COMMANDS: NOTE: all values are HEXadecimal M : show RAM, 16 lines of 16 values, from address M+ : show RAM values, from address M= : change RAM, single address M : show RAM, 16 lines of 16 values, from address 0 M+ : show RAM values, from address 0 C : show CODE/EEPROM, 16 lines of 8 values, from address C+ : show CODE/EEPROM values, from address C= : change CODE/EEPROM, single address C : show CODE/EEPROM, 16 lines of 8 values, from address 0 C+ : show CODE/EEPROM values, from address 0 G : go (start/restart/continue) F : execute function (bank bits are set to 0 before call) R : reset program (enable restart) : continue if call (not startup) H : help Example commands: M20+10 : show 0x10 bytes of RAM, from address 0x20 M20=FF : set RAM address 0x20 equal to 0xFF C100 : show program code from address 0x100 **************************************************************** DOWNLOADER: Uses INTEL HEX format: INHX8M 8 bits format: :BBaaaaTT112233...CC BB - number of 8 bit data bytes, up to 16 aaaa - hexadesimal address (byte-address) TT - type : 00 : normal 01 : end-of-file (:00000001FF) 11 - 8 bits data byte CC - checksum: adding all bytes must be 0 **************************************************************** BAUD RATE CALCULATION: async low speed: baudrate = Fosc/(64(X+1)) async high speed: baudrate = Fosc/(16(X+1)) X = value in SPBRG (0-255) X+1 = Fosc / 16 / baudrate / (1 + 3 * !BRGH) Examples X+1 Error Fosc baudrate BRGH 26.04166 0.16% 16000000 9600 0 (64) 13.02083 0.16% 16000000 19200 0 (64) 13.02083 0.16% 8000000 9600 0 (64) 104.16666 0.16% 16000000 9600 1 (16) 65.10417 0.16% 20000000 19200 1 (16) 52.08333 0.16% 16000000 19200 1 (16) --34.72222 2.12% 16000000 28800 1 (16) 26.04166 0.16% 16000000 38400 1 (16) --17.36111 2.12% 16000000 57600 1 (16) 52.08333 0.16% 8000000 9600 1 (16) 26.04166 0.16% 8000000 19200 1 (16) --17.36111 2.12% 8000000 28800 1 (16) 13.02083 0.16% 8000000 38400 1 (16) 26.04166 0.16% 4000000 9600 1 (16) 13.02083 0.16% 4000000 19200 1 (16) **************************************************************** ERROR FLAG BITS: After finishing receiving an INHX8M file, the downloader will return some information #1233:03 /00 # : / BIT error: 0 lineOverflow - too long single line (skipped) 1 dataLost - too small xtra buffer or no response to XOFF 2 framingOrOverflow - single character error (stopbit etc) 3 RecordFramingError - data record not correct 4 ChecksumError - checksum wrong 5 RecordTypeError - third byte not 0 on non-eof, or odd address 6 programmingFailed - unable to program location 7 downloaderOverwrite - attempt to overwrite downloader/monitor code **************************************************************** CHANGES IN VERSION 2 1) When AUTOSTART is defined, there will always be a full restart of the application when the EOF record is detected during download, independent of the parameter used when calling the monitor routine. 2) The prompt is displayed on various record errors during downloading. This ensures that the prompt ('>') is not lost if the download fails for some reason. 3) The display command of RAM/SFR locations above address 0x100 is corrected. 4) Corrected bug for execute single functions (F). Also, the bank selection bits are set to 0 before the call. 5) Support for the 16F87xA devices is added. Because these devices requires 4 program words to be programmed at once, the code size increases by about 100 words. 6) Two additional demo programs are added to make it clearer how to use the monitor/downloader. 7) Corrected bug to enable EEPROM contents to be included in a downloaded hex file. 8) Optional support for INHX32 records. 9) Optional support for WATCHDOG.