Communication Function With Fousb; Command Execution - Renesas M16C FAMILY User Manual

5.5.1 Communication Function with FoUSB

The clock synchronous serial I/O is used for FoUSB and the monitor program
communication. When the data is received, the DBC interrupt generates and the monitor
program is executed. The DBC interrupt is not influenced of I flag. (The receive interrupt
is used for some models because there is no DBC interrupt. In this case, the DBC
interrupt is influenced of I flag). The monitor program analyzes the received data and
executes each command.

5.5.2 Command Execution

1) User Program exection
A User Program is executed in the following procedure.
(1) An address match interrupt is disabled.
(2) One instruction of a User Program is executed (using a single step interrupt and
executing only one instruction) and go back to the monitor program.
(3) When a software break is set, enable an address match interrupt.
(4) The User Program continuance is executed.
When a User Program is stopped by a software break, if a User Program is
executed, an address match interrupt is generated and stops in the same
address again, therefore to move from the address is not possible. Above (1) to
(3) processes are performed to avoid this re-interrupt.
2) Software break
An address match interrupt is used for software break. When an address match
interrupt is generated, a monitor program is operated. The number of the software
breaks which can be used simultaneously is the same as the number of the address
match functions which are built in a microcomputer.
3) Step Execution
A single step interrupt is used for step execution. When a single step interrupt is
generated, a monitor program is operated.
return.
4) Dump
When using dump, a User Program execution is stopped temporarily, and the data
of the area currently opened in the dump window is transferred.
program is used for a register regarding a clock, therefore these registers may be
the values which the user doesn't set up.
Step execution has step, over and
67
5 Using the KD
A monitor