P R E L I M I N A R Y
X1OUT [BAUD_OUT] Clock Source
The internal clock source driving out on this pin is configured via register bits of the Function Enable Registers,
Indexes B0h and B1h.
Table 33.
BAUDOUT Pin Name
[BAUD_OUT]
Pin Type
O
X1OUT Clock Source Pin Description
X1OUT [BAUD_OUT] Pin
Description/Notes
Default Pin
Name/Function
X1OUT
Pin No.
200
Serial baud rate clock
Notes:
The default function of this pin is that no clock is driven out and the pin is tri-stated.
PC/XT Keyboard
The PC/XT keyboard functionality is enabled via bit 3 of PMU Control 3 Register, Index ADh.
Table 34.
PC/XT Keyboard Pin Name
[XTDAT]
[XTCLK]
Pin Type
I/O
I/O
XT Keyboard Pin Description
PC/XT Keyboard Pin
Description/Notes
Default Pin
Name/Function
8042CS
SYSCLK
Pin No.
75
45
Keyboard data
Keyboard clock
PCMCIA Data Path Control
Setting bit 4 of Miscellaneous 3 Register, Index BAh, enables the PCMCIA memory commands on the Parallel port
pins SLCTIN and INIT.
Table 35. PCMCIA Data Path Control
PCMCIA Control
Pin Name
[PCMCOE]
[PCMCWE]
Pin Type
O
O
Data Path Control Pin
Description/Notes
PCMCIA Output Enable
PCMCIA Write Enable
Default Pin Name/
Function
SLCTIN
INIT
Pin No.
84
89
14-MHz Clock Source
Setting bit 3 of Miscellaneous 3 Register, Index BAh, enables the 14.336-MHz clock signal on the parallel port pin
AFDT.
Table 36. 14-MHz Clock Source
14-MHz
Pin Name
[X14OUT]
Pin Type
O
14-MHz Clock Pin
Description/Notes
14.336 MHz Clock
Default Pin Name/
Function
AFDT
Pin No.
80
72
脡lan鈩C300 Microcontroller Data Sheet