Raisonance - MON-XA -ROM Monitor XA

The MON-XA executive is a ROM-Monitor for the XA family of microcontrollers. Placed at the core of an application, it provides efficient scheduling by driving:

Step by step or continuous execution.
Breakpoints.

MON-XA is easy to implement and permits the programmer to debug his/her application.
Remember that there are two different MON-XA ROM-Monitors, because the XA microcontrollers have two running modes; Page Zero and Non Page Zero.

MON-XA provides support for any compatible XA derivatives. However, it needs a communication link between the development environment (RIDE) and the target where the application is running. This link is usually achieved via the UART that is present on every compatible XA derivative and consequently this UART cannot be used elsewhere in the application. Hence the use of the ROM-Monitor has an effect on the application. However, some derivatives have more than one UART and it is possible to select which is to be used.

The ROM-Monitor is downloaded at the same time as the main program code. It is directly managed by RIDE and allows facilities such as 'step-by-step' execution and inspection of variables. If the target board can 'write to CODE space', advanced features such as 'line-by-line execution' or code breakpoints are also possible.

MON-XA consists of two parts:

The libraries (not accessible to the programmer).
The part used for communication between RIDE and the target board. The source files of this part in 'C' and Assembler are provided to allow the programmer to migrate the ROM-Monitor to a specific board/application.

MON-XA screen

RIDE allows a simplified implementation of MON-XA from two points of view:

Definition of "projects" referring to a ROM-Monitor library
Setting of the application (communication rate, code downloading, modifiable code on target...) from a dialog "Monitor" box.

Memory space contents

The contents of the different memory spaces of the current application can be visualized using in the different windows of RIDE.

It is possible, with the MON-XA ROM-Monitor, to modify the content of DATA, XDATA, SFR or BIT memory space. However the SFR registers and bits associated with the UART used by the monitor must never be modified e.g. TMOD and SCON0. In addition SFR's, SBUF SFR0 and SBUF1 must not be read.