PDI1394L41 Datasheet, PDF (19/81 Pages) NXP Semiconductors – 1394 content protection AV link layer controller

Philips Semiconductors
1394 content protection AV link layer controller
Preliminary specification
PDI1394L41
12.5.3 Big and little endianness, data invariance, and data bus width
The host interface offers programmable endianness, data invariance, and selectable 8 and 16 bit data widths. LTLEND (pin 121) and DATINV
(pin 122) are multiplexed configuration pins that will be sampled on the trailing edge of RESET; the states of these pins are established by
connecting each pin to the proper logic state, ground or V_DD, through a resistor, 22 kΩ is recommended. To verify the configuration, the shadow
register (0x0F4) will be preset to a value of 0x0F0A0500 after a power reset. Table 1 describes the configurations.
Table 1. Configuration possible combinations
LTLEND (Little Endian)
DATINV (Data Invariant)
1
1
1
0
0
X
0
X
HIF 16BIT
See Table 2
1
1
0
Result
Byte/Word address is reversed
Bytes are swapped within the word
16-bit data bus, address as in PDI1394L21
8-bit data bus, address as in PDI1394L21
Table 2. Explanation of the mode LittleEnd = 1, DataInvariant = 1
HIF16 = 0
HIF16 = 1
Outside Address (A1, A0)
Inside Address (A1, A0)
Outside Address (A1, A0)
Inside Address (A1, A0)
00
11
0X
1X
01
10
0X
1X
10
01
1X
0X
11
00
1X
0X
It is important to note that some operands in the indirect address space consist of more than one quadlet. For these operands, the lowest
address always contains the most significant quadlet.
In Bit Endian mode and DATAINV = 0, the bytes in each quadlet are numbered 0..3 from left (most significant) to right (least significant) as
shwon in Figure 4.
To access a register in 8 bit HIF mode, at address N the CPU should use addresses E:
E = N ; to access the upper 8 bits of the register.
E = N + 1 ; to access the upper middle 8 bits of the register.
E = N + 2 ; to access the lower middle 8 bits of the register.
E = N + 3 ; to access the lower 8 bits of the register.
To access a register in 16 bit HIF mode, at internal address N, the CPU should use addresses E:
E = N ;to access the upper 16 bits of the register
E = N + 2 ;to access the lower 16 bits of the register
3130 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
BYTE 0
BYTE 1
BYTE 2
BYTE 3
SV00656
Figure 4. Byte order in quadlets as implemented in the host interface, HIF LTLEND = LOW
2000 Apr 15
16