AN2548 Freescale Semiconductor / Motorola, AN2548 Datasheet - Page 6

• Manufacturer Part Number: AN2548
• Description: Serial Monitor Program for HCS12 MCUs
• Manufacturer: Freescale Semiconductor / Motorola

AN2548/D
$A1 — Read_Byte
$A2 — Write_Byte
6
Some monitor commands such as Read_Byte and Write_Byte can be
executed at any time while others may be executed only while the monitor is
active and waiting for commands (as opposed to while running user code).
Executing commands such as those that write to CPU registers would result in
unexpected program execution. If these commands are attempted while user
code is running, the command will not be executed and an error message will
be returned to the host system before issuing a new prompt.
A1/AAAA/RD — Reads a byte of data from the specified 16-bit address and
sends the 8-bit data back to the host PC. This routine assumes that accesses
to the paged memory area have been preceded by a PPAGE register access
(Write_Byte 0030 = page) to select the appropriate page.
A2/AAAA/WD — Writes the supplied byte of data to the specified 16-bit
address. This routine assumes that accesses to the paged memory area have
been preceded by a PPAGE register access (Write_Byte 0030 = page) to
select the appropriate page. All writes are processed through an intelligent
routine that programs FLASH/EEPROM or writes to RAM or registers based on
the address being written. If any error occurs during an attempt to program a
nonvolatile memory location, an error code is transmitted before a new prompt
is issued. See
RDB
WB
Abbreviation
RDB
WB
Table 1. Abbreviations Used in Command Sequences (Continued)
Freescale Semiconductor, Inc.
RDB
WB
(AAAA+1)
For More Information On This Product,
(AAAA+1)
SADR
RDW
(AAAA+NN)
WW
(AAAA+NN)
WD
NN
RD
PC
SP
(AAAA)
Serial Monitor Program for HCS12 MCUs
(AAAA)
/.../
/
/.../
/
Go to: www.freescale.com
Intelligent Writes
The number of bytes (–1) for block read and write commands
The contents of the 16-bit user program counter
One byte of read data
One word of read data
A series of 8-bit read data values from address locations
The 16-bit start address for an erase or block command
The 16-bits of the user stack pointer (SP)
One byte of write data
One word of write data
A series of 8-bit write data values for address locations
AAAA through AAAA+NN
AAAA through AAAA+NN
for details.
Definition
MOTOROLA