IDT88P8342BHGI IDT, Integrated Device Technology Inc, IDT88P8342BHGI Datasheet - Page 46

• Manufacturer Part Number: IDT88P8342BHGI
• Description: IC SPI3-SPI4 EXCHANGE 820-PBGA
• Manufacturer: IDT, Integrated Device Technology Inc

Specifications of IDT88P8342BHGI

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 88P8342BHGI

9. REGISTER DESCRIPTION
Direct access registers are used for interrupts and other high-priority registers
and for access to the indirect access registers. Direct access registers can be
accessed more quickly than indirect access registers, and are used where this
access speed advantage is required. There are only a limited number of direct
access registers due to the six address lines used on the IDT88P8342. All direct
access registers are one byte wide. Most registers within the IDT88P8342 are
of the indirect access type. Indirect access registers are used for configuration,
maps, etc., that may not need to be accessed as often as the direct registers.
9.1.1 Direct register format
access registers is shown.
TABLE 17 - BIT ORDER WITHIN AN 8-BIT DATA REGISTER
Bit 7 is the most significant data bit.
9.1.2 Indirect register format
are accessed from the external processor interface as successive bytes of
indirect data. The indirect register space includes 32-bit data registers and 8-
bit data registers. The directly-addressed register space includes directly-
addressable 8-bit data registers, four 8-bit data registers for indirect data access,
two 8-bit address registers for indirect data access, and an 8-bit control register
for indirect data access.
TABLE 18 - BIT ORDER WITHIN A 32-BIT DATA REGISTER
Bit 31 is the most significant data bit.
TABLE 19 - BIT ORDER WITHIN AN 8-BIT DATA REGISTER
Bit 7 is the most significant data bit.
IDT88P8342 SPI EXCHANGE 2 x SPI-3 TO SPI-4
Direct Register Format
bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 2 bit 0
(register 0x33)
Indirect Data (register 0x30)
bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 2 bit 0
There are two distinctly different types of register access in the IDT88P8342.
All direct register accesses are one byte. The bit ordering for the direct
The internal format for 32 and 8 bit registers is shown below. The registers
Indirect Data
bit 31…bit 25
(register 0x32)
Indirect Data
bit 24…bit 16
(register 0x31)
Indirect Data
bit 15…bit 8
8
6
C[7:0]
D[7:0]
A[5:0]
Figure 34. Direct & indirect access
(register 0x30)
Indirect Data
bit 7…bit 0
46
Indirect registers are accessed through special direct access registers designed
for the purpose of allowing indirect access to the large set of registers and maps
that are needed to configure the IDT88P8342.
9.1 Register access summary
the configuration registers. The indirect registers are accessed through a
protocol where interface pins A[5:0], D[7:0], and control pins are mapped into
internal register space A[15:0], D[31:0], and Control[7:0]. The full address of
any indirectly addressed register = Module_base + Block_base + Register_offset.
The SPI Exchange device uses an indirect addressing scheme for most of
32
16
C[7:0]
D[31:0]
A[15:0]
INDUSTRIAL TEMPERATURE RANGE
6370 drw24
APRIL 10, 2006