z8f0822 ZiLOG Semiconductor, z8f0822 Datasheet - Page 194

• Manufacturer Part Number: z8f0822
• Description: High Performance 8-bit Microcontrollers
• Manufacturer: ZiLOG Semiconductor

On-Chip Debugger Control Register Definitions
PS022517-0508
OCD Control Register
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The OCD Control Register controls the state of the OCD. This register enters or exits
DEBUG mode and enables the BRK instruction. It can also reset the Z8 Encore! XP
F0822 Series device.
Read Program Memory CRC (0EH)
computes 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
commands, there is a delay from issuing of the command until the OCD returns the
data. The OCD reads the 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 number of bytes in the Program Memory.
Step Instruction (10H)
instruction at the current Program Counter location. If the device is not in DEBUG
mode or the Read Protect Option Bit is enabled, the OCD ignores this command.
Stuff Instruction (11H)
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.
Execute Instruction (12H)
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 opcode. If
the device is not in DEBUG mode or the Read Protect Option Bit is enabled, the OCD
ignores this command
DBG ← Size[7:0]
DBG → 1-65536 data bytes
DBG ← 0EH
DBG → CRC[15:8]
DBG → CRC[7:0]
DBG ← 10H
DBG ← 11H
DBG ← opcode[7:0]
DBG ← 12H
DBG ← 1-5 byte opcode
FFFFH
—The Step Instruction command steps one assembly
—The Stuff Instruction command steps one assembly
for the CRC value. Unlike most other OCD Read
—The Execute Instruction command allows sending an
—The Read Program Memory CRC command
Z8 Encore! XP
Product Specification
®
On-Chip Debugger
F0822 Series
®
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