Stereo System User Manual

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4.12 Universal Host-Port Interface (UHPI) [C6727 Only]
4.12.1 UHPI Device-Specific Information
UHPI_HDS[2]
UHPI_HDS[1]
UHPI_HCS
UHPI_HRDY
Internal HSTROBE
Internal HRDY
TMS320C6727, TMS320C6726, TMS320C6722
Floating-Point Digital Signal Processors
SPRS268E – MAY 2005 – REVISED JANUARY 2007
The C672x DSP includes a flexible universal host-port interface (UHPI) with more options than the
host-port interface on the C671x DSP.
The UHPI on the C672x DSP supports three major operating modes listed in Table 4-9 .
Table 4-9. UHPI Major Modes on C672x
UHPI MAJOR MODE EXAMPLE FIGURE
Multiplexed Host Address/Data Half-Word (16-Bit) Mode Figure 4-15
Multiplexed Host Address/Data Fullword (32-Bit) Mode Figure 4-16
Non-Multiplexed Host Address/Data Fullword (32-Bit) Mode Figure 4-17
In all modes, the UHPI uses three select inputs ( UHPI_HCS, UHPI_HDS[2:1]) which are combined
internally to produce the internal strobe signal HSTROBE. The HSTROBE strobe signal is used in the
UHPI to capture incoming address and control signals on its falling edge and write data on its rising edge.
The UHPI_HCS signal also gates the deassertion of the UHPI_HRDY signal externally.
Figure 4-14. UHPI Strobe and Ready Interaction
The two HPI control pins UHPI_HCNTL[1:0] determine the type of access that the host will perform. Note
that only two of the four access types are supported in Non-Multiplexed Host Address/Data Fullword
Mode.
Table 4-10. HPI Access Types Selected by UHPI_HCNTL[1:0]
NON-
MULTIPLEXED MULTIPLEXED
UHPI_HCNTL[1:0] DESCRIPTION MULTIPLEXED
HALF-WORD FULLWORD
FULLWORD
00 HPI Control Register (HPIC) Access Y Y Y
01 HPI Data Access (HPID) with autoincrementing address Y Y N
10 HPI Address Register (HPIA) Access Y Y N
11 HPI Data Access (HPID) without autoincrementing Y Y Y
address
CAUTION
When performing a set of HPID with autoincrementing address accesses
(UHPI_HCNTL[1:0] = '01'), the set must begin and end at a word-aligned address. In
addition, all four of the UHPI_HBE[3:0] must be enabled on every access in the set.
CAUTION
The encoding of UHPI_CNTL[1:0] on the C672x DSP is different from HCNTL[1:0] on
the C671x DSP. Modes 01 and 10 are swapped.
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