Casio MP-2000 Service Manual page 76

XD[7:0] 122-121,119-
116, 114-113
XDIR 112
RTCAS/ 94
PCWE0
ROMCS# / 135
KBCS#
PCWE1 93
USBDATA0+ 95
USBDATA0- 96
USBDATA1+ 97
USBDATA1- 98
USBCLK 99
KBCK / 108
KA20G
KBDT/ 109
KBRC#
XD Interface
5v B X-BUS DATA BUS:
These pins are used as strap option during the
power-up:
5v O X-BUS DIRECTION: XIDR# is tied directly to the
direction control of a 74F245 that buffer the X-Bus
data and ISA-Bus data.
5v O Multifunction Pin:
Internal RTC disable:
Internal RTC enable:
5v O ROM CHIP SELECT / KEYBOARD
CONTROLLER CHIP SELECT: Multi-function pin
Normal Operation
Power-up
5v O GENERAL PURPOSE WRITE ENABLE 1:
LATCH enable signal to a external 373 for general
outputs.
Universal Serial Bus Interface
usb B USB PORT 0 DATA:
usb B USB PORT 0 DATA:
usb B USB PORT 1 DATA:
usb B USB PORT 1 DATA:
usb I USB CLOCK: Clock input for Universal serial bus
interface
Keyboard Interface
5v B Multifunction Pin:
Internal Keyboard controller enable:
Internal Keyboard controller disable:
KEYBOARD GATE A20: GATE A20 output
from external keyboard controller.
5v B Multifunction Pin:
Internal Keyboard controller enable:
KEYBOARD DATA: DATA to keyboard interface.
Internal Keyboard controller disable:
KEYBOARD RESET: Reset input from external
keyboard controller.
— 75 —
XD0: 0/l - Disable/enable internal KBC
XD1: 0/l - Disable/enable internal PS/2 Mouse.
XD2: 0/l - Disable/enable internal RTC
XD3: 0/l - PIA/SIO
XD4~XD7: RP13~RP16 for internal KBC
REAL TIME CLOCK ADDRESS STROBE:
RTCAS is connected directly to the address strobe
input of the external RTC.
GENERAL PURPOSE WRITE ENABLE 1:
LATCH enable signal to a external 373 for general
outputs.
ISA memory cycle: Chip-select to the ROM-BIOS
ISA I/O cycle: Chip-select to the external
keyboard controller.
0: DACKx by external 137, DACK0 as DACEN,
DACK1-7 as EXTSMI
1: DACKx as DACKx
KEYBOARD CLOCK: CLOCK to keyboard interface.