Pci Mode (Hm = $1); Universal Bus Mode (Hm = $2) - Motorola DSP56305 User Manual

HOST INTERFACE (HI32)
DSP SIDE Programming Model
6.5.1.13.2

PCI Mode (HM = $1)

The HI32 supports:
• Glueless connection to the standard PCI bus.
• Operation as an initiator (master) or target (slave).
• 24- to 32-bit, 32- to 24-bit data formatting and true 32-bit (Dword) data transfers.
• Memory-space and configuration transactions as a target.
• Memory-space, I/O-space and configuration transactions as an initiator.
6.5.1.13.3

Universal Bus Mode (HM = $2)

The HI32 supports:
• Slave-only glueless connection to various external buses (e.g. ISA/EISA,
DSP56300 core based DSP Port A bus).
• 24-, 16- (with data alignment), and 8-bit buses.
• ISA/EISA bus DMA-type accesses.
• Pins HP22-HP20 are general purpose I/O.
• HP19, HP31 and HP32 are unused and must be forced or pulled up to Vcc.
• When operating with a host bus less than 24 bits wide, the data signals that are
not used for transferring data must be forced or pulled up or down to Vcc or to
GND respectively. For example: when operating with a 16-bit bus (e.g. ISA bus),
HP48-HP41 must be forced or pulled up to Vcc or pulled down to GND.
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