bootloader log.txt

c8051f310xmodembootloader.rar

/******************************************************************************
** 	about bootloader 	 MCU:C8051F310
******************************************************************************/

bootloader:0x0000-0x1000
        AP:0x1000-0x3dff
  reserved:0x3dff-0x3fff


1,建立bootloader.c
  加入startup.a51
  在startup.a51(默认) 里面第120行 加入如下 中断向量 函数地址映射
  如下:
  	ORG	0000BH    /*定时器0*/
	LJMP	0100BH    /*跳转到用户代码区1000h以后*/
        ...               /*所有中断*/
        ...
  在bootloader.c 中加入跳转到AP区的指令
  如下:
        ((void(code *)(void))0x1100)();  /*0x1100 为startup.a51的地址*/
                                         /*一般放在 中断映射后的地址*/


  编译:烧录从0x0000开始


2,建立AP.C 用户代码
  加入startup.a51  (可以不加)
  在keil->options->c51->interrupt vectors at address: 输入中断映射地址
  如下: 
       interrupt vectors at address: 0x1000 
  0x1000即AP的code区起始地址 也是中断矢量地址的映射基地址开始。

  在keil->options->BL51 Locate 设置如下
  定义 code Rang 0x1000-0x3dff
  CODE: 输入 ?C_C51STARTUP(1100H)        /*需要和bootloader中的跳转地址一致*/
                                         /*只需要定位好这个地址*/
                                         /*这样所有的中断函数都不需要再次定位*/

  编译：烧录的时候 从0x1000 开始烧 即第7块开始

  两个代码烧录完,复位就可以运行
  
3,bootloader区串口等下载 不能出现中断函数



另外一种IAP方法

前3字节 0000 0001 0002 做跳转

用户代码区 0000-(IAP-512)区 但前3字节不允许修改 而烧录的实际前3字节保存在IAP 前512字节里面
                            用于跳转进入用户代码
IAP区 在程序的最后几k字节 固定不允许修改 而0000 0001 0002这三字节地址的数据 存IAP的初始代码地址

问题2个,iap也不能用中断程序 ,如果刚好擦掉0000开始的地址一页 断点了那么无法恢复 进入IAP的指令


/******************************************************************************
** 	 The Xmodem Protocol Specification 
******************************************************************************/

The Xmodem Protocol Specification 

MODEM PROTOCOL OVERVIEW

1/1/82 by Ward Christensen. I will maintain a master copy of
this. Please pass on changes or suggestions via CBBS/Chicago
at [phone], or by voice at [phone].

NOTE this does not include things which I am not familiar with,
such as the CRC option implemented by John Mahr.

Last Rev: (none)

At the request of Rick Mallinak on behalf of the guys at
Standard Oil with IBM P.C.s, as well as several previous
requests, I finally decided to put my modem protocol into
writing. It had been previously formally published only in the
AMRAD newsletter.

Table of Contents
1. DEFINITIONS
2. TRANSMISSION MEDIUM LEVEL PROTOCOL
3. MESSAGE BLOCK LEVEL PROTOCOL
4. FILE LEVEL PROTOCOL
5. DATA FLOW EXAMPLE INCLUDING ERROR RECOVERY
6. PROGRAMMING TIPS.

-------- 1. DEFINITIONS.
<soh> 01H
<eot> 04H
<ack> 05H
<nak> 15H
<can> 18H

-------- 2. TRANSMISSION MEDIUM LEVEL PROTOCOL
Asynchronous, 8 data bits, no parity, one stop bit.

The protocol imposes no restrictions on the contents of the
data being transmitted. No control characters are looked for
in the 128-byte data messages. Absolutely any kind of data may
be sent - binary, ASCII, etc. The protocol has not formally
been adopted to a 7-bit environment for the transmission of
ASCII-only (or unpacked-hex) data , although it could be simply
by having both ends agree to AND the protocol-dependent data
with 7F hex before validating it. I specifically am referring
to the checksum, and the block numbers and their ones-
complement.
Those wishing to maintain compatibility of the CP/M file
structure, i.e. to allow modemming ASCII files to or from CP/M
systems should follow this data format:
* ASCII tabs used (09H); tabs set every 8.
* Lines terminated by CR/LF (0DH 0AH)
* End-of-file indicated by ^Z, 1AH. (one or more)
* Data is variable length, i.e. should be considered a
continuous stream of data bytes, broken into 128-byte
chunks purely for the purpose of transmission. 
* A CP/M "peculiarity": If the data ends exactly on a
128-byte boundary, i.e. CR in 127, and LF in 128, a
subsequent sector containing the ^Z EOF character(s)
is optional, but is preferred. Some utilities or
user programs still do not handle EOF without ^Zs.
* The last block sent is no different from others, i.e.
there is no "short block". 

-------- 3. MESSAGE BLOCK LEVEL PROTOCOL
Each block of the transfer looks like:
<SOH><blk #><255-blk #><--128 data bytes--><cksum>
in which:
<SOH> = 01 hex
<blk #> = binary number, starts at 01 increments by 1, and
wraps 0FFH to 00H (not to 01)
<255-blk #> = blk # after going thru 8080 "CMA" instr, i.e.
each bit complemented in the 8-bit block number.
Formally, this is the "ones complement".
<cksum> = the sum of the data bytes only. Toss any carry.

-------- 4. FILE LEVEL PROTOCOL

---- 4A. COMMON TO BOTH SENDER AND RECEIVER:

All errors are retried 10 times. For versions running with
an operator (i.e. NOT with XMODEM), a message is typed after 10
errors asking the operator whether to "retry or quit".
Some versions of the protocol use <can>, ASCII ^X, to
cancel transmission. This was never adopted as a standard, as
having a single "abort" character makes the transmission
susceptible to false termination due to an <ack> <nak> or <soh>
being corrupted into a <can> and canceling transmission.
The protocol may be considered "receiver driven", that is,
the sender need not automatically re-transmit, although it does
in the current implementations.

---- 4B. RECEIVE PROGRAM CONSIDERATIONS:
The receiver has a 10-second timeout. It sends a <nak>
every time it times out. The receiver's first timeout, which
sends a <nak>, signals the transmitter to start. Optionally,
the receiver could send a <nak> immediately, in case the sender
was ready. This would save the initial 10 second timeout. 
However, the receiver MUST continue to timeout every 10 seconds
in case the sender wasn't ready.
Once into a receiving a block, the receiver goes into a
one-second timeout for each character and the checksum. If the
receiver wishes to <nak> a block for any reason (invalid
header, timeout receiving data), it must wait for the line to
clear. See "programming tips" for ideas
Synchronizing: If a valid block number is received, it
will be: 1) the expected one, in which case everything is fine;
or 2) a repeat of the previously received block. This should
be considered OK, and only indicates that the receivers <ack>
got glitched, and the sender re-transmitted; 3) any other block
number indicates a fatal loss of synchronization, such as the
rare case of the sender getting a line-glitch that looked like
an <ack>. Abort the transmission, sending a <can>

---- 4C. SENDING PROGRAM CONSIDERATIONS.

While waiting for transmission to begin, the sender has
only a single very long timeout, say one minute. In the
current protocol, the sender has a 10 second timeout before
retrying. I suggest NOT doing this, and letting the protocol
be completely receiver-driven. This will be compatible with
existing programs.
When the sender has no more data, it sends an <eot>, and
awaits an <ack>, resending the <eot> if it doesn't get one. 
Again, the protocol could be receiver-driven, with the sender
only having the high-level 1-minute timeout to abort.

-------- 5. DATA FLOW EXAMPLE INCLUDING ERROR RECOVERY

Here is a sample of the data flow, sending a 3-block message.
It includes the two most common line hits - a garbaged block,
and an <ack> reply getting garbaged. <xx> represents the
checksum byte.

SENDER RECEIVER
times out after 10 seconds,
                        <--- <nak>
<soh> 01 FE -data- <xx> --->
                        <--- <ack>
<soh> 02 FD -data- xx   ---> (data gets line hit)
                        <--- <nak>
<soh> 02 FD -data- xx   --->
                        <--- <ack>
<soh> 03 FC -data- xx   --->
    (ack gets garbaged) <--- <ack>
<soh> 03 FC -data- xx   ---> <ack>
<eot>                   --->
                        <--- <ack>

-------- 6. PROGRAMMING TIPS.

* The character-receive subroutine should be called with a
parameter specifying the number of seconds to wait. The
receiver should first call it with a time of 10, then <nak> and
try again, 10 times.
After receiving the <soh>, the receiver should call the
character receive subroutine with a 1-second timeout, for the
remainder of the message and the <cksum>. Since they are sent
as a continuous stream, timing out of this implies a serious
like glitch that caused, say, 127 characters to be seen instead
of 128.

* When the receiver wishes to <nak>, it should call a "PURGE"
subroutine, to wait for the line to clear. Recall the sender
tosses any characters in its UART buffer immediately upon
completing sending a block, to ensure no glitches were mis-
interpreted.
The most common technique is for "PURGE" to call the
character receive subroutine, specifying a 1-second timeout,
and looping back to PURGE until a timeout occurs. The <nak> is
then sent, ensuring the other end will see it.

* You may wish to add code recommended by Jonh Mahr to your
character receive routine - to set an error flag if the UART
shows framing error, or overrun. This will help catch a few
more glitches - the most common of which is a hit in the high
bits of the byte in two consecutive bytes. The <cksum> comes
out OK since counting in 1-byte produces the same result of
adding 80H + 80H as with adding 00H + 00H.