Gcsr Method - Motorola MVME162LX 300 Series Installation And Use Manual

Debugger General Information
3

GCSR Method

3-22
If the code being executed in dual-port RAM is to reenter the debug
monitor, a TRAP #15 call using function $0063 (SYSCALL .RETURN)
returns control to the monitor with a new display prompt. Note that every
time the debug monitor returns to the prompt, an R is moved into the
MPCR to indicate that control can be transferred once again to a specified
RAM location.
A remote processor can initiate program execution in the local
MVME162LX dual-port RAM by issuing a remote GO command using
the VMEchip2 Global Control and Status Registers (GCSR). The remote
processor places the controller's execution address in general purpose
registers 0 and 1 (GPCSR0 and GPCSR1). The remote processor then sets
bit 8 (SIG0) of the VMEchip2 LM/SIG register. This causes the controller
to install breakpoints and begin execution. The result is identical to the
MPCR method (with status code B) described in the previous section.
The GCSR registers are accessed in the VMEbus short I/O space. Each
general purpose register is two bytes wide, occurring at an even address.
The general purpose register number 0 is at an offset of $8 (local bus) or
$4 (VMEbus) from the start of the GCSR registers. The local bus base
address for the GCSR is $FFF40100. The VMEbus base address for the
GCSR depends on the group select value and the board select value
programmed in the Local Control and Status Registers (LCSR) of the
controller. The execution address is formed by reading the GCSR general
purpose registers in the following manner:
GPCSR0 used as the upper 16 bits of the address
GPCSR1 used as the lower 16 bits of the address
The address appears as:
GPCSR0 GPCSR1
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