Motorola M68CPU32BUG Uživatelský manuál stáhnout pdf (Strana 32)

DEBUG MONITOR COMMANDS

M68CPU32BUG/D REV 1 3-32

LO Load S-Records From Host LO

Other options:

-C Ignore checksum. A checksum for the data contained within an S-record is

calculated as the S-record is read in through the port. Normally this calculated

checksum is compared to the checksum contained within the S-record. If the

compare fails, an error message is sent to the screen on completion of the

download. If this option is selected, then the comparison is not made.

X Echo. As the S-records are read in at the host port, they are echoed to the user’s

terminal. Do not use this option when port 0 is specified.

T TRAP #15 code. This option causes LO to set the target register D4 = ’LO’x, with

x = $0C ($4C4F200C). The ASCII string ’LO’ indicates that this is the LO

command; the code $0C indicates TRAP #15 support with stack parameter/result

passing and TRAP #15 disk support. This code is used by the downloaded

program to select the appropriate calling convention when executing debugger

functions. Since some Motorola debuggers use conventions different from

CPU32Bug, they set a different code in D4.

The S-record format (refer to Appendix A) allows a specified entry point in the address field of

the S-record-block termination record. The contents of the termination-record address field (plus

any offset address) is put into the target PC. Thus after a download the user need only enter G or

GO instead of G <addr> or GO <addr> to execute the downloaded code.

If a non-hex character is encountered within the data field of a data record, then that part of the

record, preceeding the non-hex character, is displayed. This causes the CPU32Bug error handler

to point at the faulty character.

An error condition exists if the embedded-record checksum does not agree with the checksum

calculated by CPU32Bug. An output message displays the address of the record (as obtained

from the address field of the record), the calculated checksum, and the checksum read with the

record. A copy of the record is also output. A checksum error is a fatal error and causes the

command to abort.

When a load is in progress, each data byte is written to memory and then the contents of this

memory location are compared to the data to determine if the data is stored properly. If for some

reason the compare fails, then an output message displays the address where the data was to be

stored, the data written, and the data read back during the compare. This is also a fatal error and

causes the command to abort.

S-records are processed character-by-character. So if the command aborts due to an error, all data

stored previous to the error is still in memory .

DEBUG MONITOR COMMANDS

M68CPU32BUG/D REV 1 3-33

LO Load S-Records From Host LO

EXAMPLES Suppose a host computer was used to create a program that looks like this:

1 * Test Program.

3 65004000 ORG $65004000

5 65004000 7001 MOVEQ.L #1,D0

6 65004002 D088 ADD.L A0,D0

7 65004004 4A00 TST.B D0

8 65004006 4E75 RTS

9 END

****** TOTAL ERRORS 0--

****** TOTAL WARNINGS 0--

Then this program was converted into an S-record file named TEST.MX as follows:

S00F00005445535453335337202001015E

S30D650040007001D0884A004E7577

S7056500400055

Load this file into BCC memory for execution at address $4000 as follows:

CPU32Bug>LO -65000000<CR>

Blank line as the BCC waits for an S-record.

Enter the terminal emulator’s escape key to return to the host computer’s operating system (ALT-

F4 for ProComm). A host command is then entered to send the S-record file to the port where the

BCC is connected (for MS-DOS based host computer this would be "type test.mx >com1", where

the BCC was connected to the com1 port).

After the file has been sent, the user then restarts the terminal emulation program (for MS-DOS

based host computers, enter EXIT at the prompt).

Since the port number equals the current terminal, two <CR>’s are required to signal CPU32Bug

that the download is complete and the terminal emulation program is ready to receive any error

messages.

<CR><CR> Signal download completion.

CPU32Bug> No error messages.

eescale S

emiconduct

, I

Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com

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