Integrated Technology Express, Inc.
Application Note of IT887X
IT887x On Board Design Reference Guide V1.0
Feb. 18, 2002
Reversion History
Reversion
Change List
V1.0
Note
First Draft
IT887x design for card using INTA# (Sharing IRQx), driver auto detect IRQx & assign I/O address for IT887x.
If customer intends to add more serial or parallel ports on their board, it is strongly recommended that SERIRQ# is
Note
used instead of INTA#. IT887x doesn鈥檛 need the driver, except the dummy driver , thereby avoiding the
compatibility issue. SERIRQ# can be used to set UART1, UART2, Parallel port interrupt routing to SERIRQ via the
serial EEPROM (SM-bus). All ports can be set to different IRQx & I/O addresses.
Note: Because IT887x is a PNP device, it needs a dummy driver to cover 鈥?鈥?signal in Windows system.
Here is an example for IT8872 on board design, using SERIRQ.
Reset-Strap Setting
Symbol
CSA0#
Jumper
(P/UP)
P/Down
INTA#
SERIRQ#
Function Description
Programming steps:
a. Set Internal UART1, UART2 and Parallel Ports Base Address
===> IT8872鈥檚 configuration 7Ch<15::00>=03,F8h (UART1)
===> IT8872鈥檚 configuration 7Ch<31::16>=02,F8h (UART2)
===> IT8872鈥檚 configuration 80h<15::00>=03,78h (Internal LPT)
===> IT8872鈥檚 configuration 80h<31::16>=07,78h (Internal LPT for ECP)
b. Positive Decode UART1, UART2 and Parallel Ports I/O Base Address
===> IT8872鈥檚 configuration 60h<31::0>=E3,00,03,F8h (UART1)
===> IT8872鈥檚 configuration 64h<31::0>=E3,00,02,F8h (UART2)
===> IT8872鈥檚 configuration 68h<31::0>=E3,00,03,78h (Internal LPT)
===> IT8872鈥檚 configuration 6Ch<31::0>=E3,00,07,78h (Internal LPT for ECP)
c. Set Internal UART1, UART2 and Parallel Ports鈥?Interrupt Routing
===> IT8872鈥檚 configuration 9Ch<15::12>=0100b (UART1)
===> IT8872鈥檚 configuration 9Ch<11::08>=0011b (UART2)
===> IT8872鈥檚 configuration 9Ch<07::04>=0111b (Internal LPT)
d. Set Internal Parallel Ports鈥?Mode & DMA Channel
===> IT8872鈥檚 configuration 9Ch<31::30>=11b (SPP & EPP & ECP mode)
===> IT8872鈥檚 configuration 9Ch<29::27>=011b (DMA channel_3)
e. Enable Internal UART1, UART2 and Parallel Ports鈥?control
===> IT8872鈥檚 configuration 9Ch<23::21>=111b
ITTM-AN-02002
By : Greg
Check : Gary
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