80 likes | 150 Vues
NS9750 - Training Hardware. NS9750 CardBus Support. CardBus Support. Supports 32-bit PC Cards as defined in the PC Card Standard Release 8 (specification available at www.pcmcia.org ) Supports maximum specified bus speed of 33Mhz On-chip CardBus arbiter which always parks bus on NS9750
E N D
CardBus Support • Supports 32-bit PC Cards as defined in the PC Card Standard Release 8 (specification available at www.pcmcia.org) • Supports maximum specified bus speed of 33Mhz • On-chip CardBus arbiter which always parks bus on NS9750 • Who ever was the last owner of the bus remains that until some other module requests the bus owbership • Acts only as a CardBus Host • Provides CardBus Central Resource functions • CardBus clock can be provided by NS9750 • Configured for CardBus via single hardware strapping pin (BOOT_STRAP[1]) • Supports CardBus Socket Registers • Supports all CardBus interrupt sources (e.g. CINT#,CSTSCHG)
CardBus Limitations • No support for 16-bit PC Cards (aka PCMCIA) • Socket controller functions (e.g. card interrogation) normally done in hardware by commercial CardBus controllers done in software with minimal hardware support via the CardBus Miscellaneous Support Register • Tailored towards embedded applications where CardBus card is present in socket when system is powered
NS9750 CardBus Configuration • PCI_CENTRAL_RSC_N (Internal pull-down) must be “0” to provide Central Resource Functions, i.e. System clock, the driving of the address lines and etc. • RTCK (Internal pull-up) must be “1” to enable internal arbiter • BOOT_STRAP[1] (Internal pull-up) must be “0” to put in CardBus mode • IDSEL must be “1” since CardBus does not support this pin. • Series resistors may be required close to NS9750 pins to limit slew-rate • The system must provide pull-up or pull-down resistors on signals: • CFRAME#,CTRDY#,CIRDY#,CDEVSEL#,CSTOP#,CPERR#, CINT#(pull-up) • CSERR#, CREQ#,CGNT#,CCLKRUN#,CCD1,CCD2,INTD# (pull-up) • CSTSCHG (pull-down) • See PCI FAQ for additional information
Hints & Kinks • How long can the CardBus traces between the NS9750 and the CardBus connector be? • There is no maximum length specified. However, the total capacitive load presented by the system to a CardBus device (i.e. NS9750, connector, trace, and vias) must be less than 22pf. • Does the NS9750 support CardBus and PCI devices at the same time? • No, the NS9750 can be configured for either PCI or CardBus, but not both. • How many external CardBus devices does the NS9750 support? • The CardBus is designed for point-to-point connection of a host and one external CardBus device.