Z8F4822AR020SG Datasheet, PDF (212/323 Pages) Zilog, Inc. – High Performance 8-Bit Microcontrollers

Z8 Encore! XP^® F64xx Series
Product Specification
192
Read Data Memory (0DH). The Read Data Memory command reads from Data Memory.
This command is equivalent to the LDE and LDEI instructions. Data can be read 1-65536
bytes at a time (65536 bytes can be read by setting size to zero). If the device is not in
DEBUG Mode, this command returns FFH for the data.
DBG ← 0DH
DBG ← Data Memory Address[15:8]
DBG ← Data Memory Address[7:0]
DBG ← Size[15:8]
DBG ← Size[7:0]
DBG 1-65536 data bytes
Read Program Memory CRC (0EH). The Read Program Memory CRC command com-
putes and returns the CRC (cyclic redundancy check) of program memory using the 16-bit
CRC-CCITT polynomial. If the device is not in DEBUG Mode, this command returns
FFFFH for the CRC value. Unlike most other OCD Read commands, there is a delay from
issuing of the command until the OCD returns the data. The OCD reads program memory,
calculates the CRC value, and returns the result. The delay is a function of the program
memory size and is approximately equal to the system clock period multiplied by the num-
ber of bytes in program memory.
DBG ← 0EH
DBG CRC[15:8]
DBG CRC[7:0]
Step Instruction (10H). The Step Instruction command steps one assembly instruction at
the current Program Counter (PC) location. If the device is not in DEBUG Mode or the
Read Protect option bit is enabled, the OCD ignores this command.
DBG ← 10H
Stuff Instruction (11H). The Stuff Instruction command steps one assembly instruction
and allows specification of the first byte of the instruction. The remaining 0-4 bytes of the
instruction are read from program memory. This command is useful for stepping over
instructions where the first byte of the instruction has been overwritten by a breakpoint. If
the device is not in DEBUG Mode or the Read Protect option bit is enabled, the OCD
ignores this command.
DBG ← 11H
DBG ← opcode[7:0]
Execute Instruction (12H). The Execute Instruction command allows sending an entire
instruction to be executed to the eZ8 CPU. This command can also step over breakpoints.
The number of bytes to send for the instruction depends on the op code. If the device is not
in DEBUG Mode or the Read Protect option bit is enabled, the OCD ignores this com-
mand
DBG ← 12H
DBG ← 1-5 byte opcode
PS019924-0113
PRELIMINARY
On-Chip Debugger Commands