HPI Signal Descriptions
7-8
Table 7–2. HPI Input Control Signals Function Selection Descriptions
HCNTL1
HCNTL0
Description
0
0
Host reads from or writes to the HPI control register (HPIC).
0
1
Host reads from or writes to the HPI address register (HPIA).
1
0
Host reads or writes to the HPI data register (HPID). The HPI
address register (HPIA) is postincremented by a word ad-
dress (four byte addresses).
1
1
Host reads or writes to the HPI data register (HPID). HPI ad-
dress register (HPIA) is not affected.
7.2.3
Halfword Identification Select: HHWIL
HHWIL identifies the first or second halfword of a transfer, but not the most sig-
nificant or least significant halfword. The status of the HWOB bit of the HPIC
register, described later in this chapter, determines which halfword is least sig-
nificant or most significant. HHWIL is low for the first halfword and high for the
second halfword.
Since byte enable pins are removed from the ’C6211/C6711 HPI, HHWIL in
combination with HWOB specify the half-word position in the data register,
HPID. This is shown in Table 7–3 along with the LSB address bits depending
on endianness.
Table 7–3. HPI Data Write Access
Data-Type
Little-Endian (LE)/
Big-Endian (BE)
HWOB
First Write
(HHWIL=0) /
Logical LSB
Address Bits
Second Write
(HHWIL=1) /
Logical LSB
Address Bits
Half-word:
Little endian (LE)
Big endian (BE)
0
MS half-word
LE = 10
BE = 00
LS half-word
LE = 00
BE = 10
Half-word:
Little endian (LE)
Big endian (BE)
1
LS half-word
LE = 00
BE = 10
MS half-word
LE = 10
BE = 00
Word:
Little endian (LE)
Big endian (BE)
0
MS half-word
LE = 00
BE = 00
LS half-word
LE = 00
BE = 00
Word:
Little endian (LE)
Big endian (BE)
1
LS half-word
LE = 00
BE = 00
MS half-word
LE = 00
BE = 00