Texas Instruments TMS320C6457 manual HPI Operation, Host-HPI Signal Connections

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3 HPI Operation

3.1Host-HPI Signal Connections

Figure 2 and Figure 3 show examples of signal connections for the 32-bit multiplexed mode. Figure 4 and Figure 5 show similar examples for the 16-bit multiplexed mode. In Figure 2 and Figure 4, the HAS signal is used as described in Section 3.6. In Figure 3 and Figure 5, HAS is tied high (not used). Note the following key comparisons between the signal connections in the two interface modes:

•The HPI_WIDTH configuration pin of the DSP must be held high at reset for the 32-bit multiplexed mode (HPI32) or low at reset for the 16-bit multiplexed mode (HPI16).

•The address strobe (HAS) of the HPI is optional for both modes.

•The halfword identification control line (HHWIL) of the HPI is not used in the 32-bit multiplexed mode, but is required in the 16-bit multiplexed mode.

CAUTION

Note that the encoding of HCNTL0 and HCNTL1 for the different types of HPI accesses varies on many TI DSPs; therefore, you should use caution to ensure that the correct encoding of these inputs is used for your device. The encoding of these signals as described in this document applies only to C6457 DSPs.

Figure 2. Example of Host-DSP Signal Connections When Using the HAS Signal

in the 32-Bit Multiplexed Mode

Host

Address latch enable

Address or I/O

Read/Write

Chip select

Data strobeA

Data/address

Ready

Interrupt

2

No connect

Logic high

32

DSP

HPI

HAS

HCNTL[1:0]

HHWIL

HR/W

HCS

HDS1

HDS2

HD[31:0]

HRDY

HINT

A Data strobing options are given in Section 3.3.

12 Host Port Interface (HPI) SPRUGK7A –March 2009 –Revised July 2010

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