HP 64751 User Manual page 134

Chapter 5: Configuring the Emulator
Mapping Memory
You should map all memory ranges used by your programs before loading
programs into memory.
Using Emulation Memory to Substitute for 8-Bit Memory
Emulation memory is 16-bit wide memory. However, you can use emulation
memory to substitute for 8-bit memory by using one of the chip selects and
generating internal DSACKx signals for an 8-bit port. You must place the
appropriate values into the emulator configuration (CF_SIM) versions of the chip
select address and mask registers so that emulation memory is accessed correctly.
Using Chip Selects to Access Emulation Memory
When using chip selects to access emulation memory, the DSACKx signals can be
generated internally or externally.
If the DSACKx signals are generated externally (as defined by the
CF_CSXMASK register), emulation memory must be interlocked with the target
system (use the dsi attribute when mapping the emulation memory range);
otherwise, there will be no DSACKx response.
Fast Termination Mode
Emulation memory does not support the fast termination mode (-1 wait state) that
can be defined in the chip select registers. If a chip select is programmed for this
mode, it will override the mapper and force access to the target system.
External DMA Access to Emulation Memory
External direct memory access (DMA) to emulation memory is not permitted.
The HP 64751 emulator supports operation of the two 68340 on-chip DMA
channels in both single- and dual-address modes. Dual-address transfers can access
emulation memory; single-address transfers must be between peripherals and
memory in the target system only.
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