Motorola 68HC08LD - Manual (Page 3)

 iSYSTEM, March 2004 3/12
For every POD the following information is given:
• Ordering code. If there are different speed versions of a POD the ordering code is modified by appending
the speed in MHz (IC81020-16 for the 16 MHz 8031 POD)
• information on available speed versions and required Emulator access time
• POD size and position of PIN1 on the target adapter relative to bottom left corner.
The memory range specifies the range of addresses that a POD can address. If this specification is omitted the
default 1MB is assumed.
Note: The In-Circuit Emulator can emulate a processor or a microcontroller. Beside the CPU, additional logic is
integrated on the POD. The amount of additional logic depends on the emulated CPU and the type of emulation.
A buffer on a data bus is always used (minimal logic) and when rebuilding ports on the POD, maximum logic is
used. As soon as a POD is inserted in the target instead of the CPU, electrical and timing characteristics are
changed. Different electrical and timing characteristics of used elements on the POD and prolonged lines from
the target to the CPU on the POD contribute to different POD characteristics. Consequently, signal cross-talks
and reflections occur, capacitance changes, etc.
Beside that, pull-up and pull-down resistors are added to some signals. Pull-up/pull-down resistors are required
to define the inactive state of signals like reset and interrupt inputs, while the POD is not connected to the target.
Because of this, the POD can operate as standalone without the target.
Final Target Application Test
After the application is being more or less debugged and final application test is performed, it is recommended to
remove all breakpoints and to close all debug windows (memory, SFR, watch...) to eliminate any possible
influence of the emulator on the CPU execution. There were cases where the target application has been
behaving differently with the target CPU inserted or the POD connected. If the debugger is configured to update
some debug windows in real-time, the user may not be aware of that the CPU execution may be slightly
disturbed. However, when the monitor access type is configured to update debug windows while the CPU is
running, the CPU execution is disturbed significantly, depending on the necessary number of memory accesses
to update opened debug windows.
There are cases when internal peripheral device requires read access of the particular register during the device
configuration. The user has had SFR window opened and the necessary read access was actually performed by
the debugger and not by the application as it would be correct. Therefore, the application was working fine with
the emulator, but a standalone application didn't work correctly, as the peripheral device was not configured
properly.
For Better Understanding of the Hardware Reference: PIN 1 locations
There are several references to pin 1 in the manual and many jumper settings, CPU and pinout orientations rely
on the correct location of pin 1. If sometimes the location of pin 1 is not clear, check the markings on the POD.
If there are no markings, check the PCB board of the POD. Pin 1 is always marked on the PCB with a square pin
(the other pins are round). The pin 1 location is also visible on the board in the hardware reference, if not any
other way it can be identified by searching for the square pin.