ISP1181BBS,551 NXP Semiconductors, ISP1181BBS,551 Datasheet - Page 17

• Manufacturer Part Number: ISP1181BBS,551
• Manufacturer: NXP Semiconductors

Specifications of ISP1181BBS,551

• Operating Temperature (max): 85C
• Operating Temperature (min): -40C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 48
• Lead Free Status / RoHS Status: Compliant

ISP1181B_3
Product data sheet
10.2 8237 compatible mode
Table 7.
The 8237 compatible DMA mode is selected by clearing bit DAKOLY in the Hardware
Configuration Register (see
Table
Table 8.
The DMA subsystem of an IBM compatible PC is based on the Intel 8237 DMA controller.
It operates as a ‘fly-by’ DMA controller: the data is not stored in the DMA controller, but it
is transferred between an I/O port and a memory address. A typical example of ISP1181B
in 8237 compatible DMA mode is given in
The 8237 has two control signals for each DMA channel: DREQ (DMA Request) and
DACK (DMA Acknowledge). General control signals are HRQ (Hold Request) and HLDA
(Hold Acknowledge). The bus operation is controlled via MEMR (Memory Read), MEMW
(Memory Write), IOR (I/O read) and IOW (I/O write).
Symbol
DREQ
DACK
EOT
RD
WR
Fig 4.
Endpoint
identifier
8.
12
13
14
ISP1181B in 8237 compatible DMA mode.
Endpoint selection for DMA transfer
8237 compatible mode: pin functions
Description
DMA request
DMA acknowledge
end of transfer
read strobe
write strobe
DATA1 to DATA15
ISP1181B
Rev. 03 — 23 January 2009
DREQ
DACK
EPIDX[3:0]
AD0,
WR
RD
1101
1110
1111
Table
20). The pin functions for this mode are shown in
I/O
O
I
I
I
I
RAM
Figure
MEMR
MEMW
DREQ
DACK
IOR
IOW
EPDIR = 0
…continued
OUT: read
OUT: read
OUT: read
CONTROLLER
Function
ISP1181B requests a DMA transfer
DMA controller confirms the transfer
DMA controller terminates the transfer
instructs ISP1181B to put data on the bus
instructs ISP1181B to get data from the bus
4.
Full-speed USB peripheral controller
DMA
8237
Transfer direction
HLDA
HRQ
© ST-NXP Wireless 2009. All rights reserved.
HRQ
HLDA
ISP1181B
CPU
004aaa137
EPDIR = 1
IN: write
IN: write
IN: write
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