Port J - Motorola DragonBall MC68328 User Manual

DIRECTION- DIR[7:0]
These bits control the direction of the pins. While high, the pins are outputs. While low,
the pins are inputs. These bits reset to 0 and have no function while the SELECT bits are
low.
DATA- D[7:0]
These bits control or report the data on the pins while the associated SELECT bits are
high. While the DIRECTION bits are high, the DATA bits control the pins. While the DI-
RECTION bits are low, the actual levels on the pins are reported. These bits reset to 0
while the SELECT bits are low. The data bits may be written at any time. Bits that are con-
figured as inputs will accept the written data but it will not be accessible until the respective
pins are configured as outputs. Note that the actual value on the pin is reported when
these bits are read.
While PC0MOCLK is high, the RTCOUT bit is disabled and be-
comes an input for the 32 KHz real-time clock reference.
PULLUP - PU[7:0]
These bits enable the pullup resistors on the port. While high, the pullup resistors are en-
abled; while low, they are disabled. Port E, bit 7 pullup resistor is enabled after reset.
SELECT- SEL[7:0]
These bits select whether the various functions or port I/O signals are connected to the
pins. While high, the port I/O function is connected to the pin. While low, the various func-
tions are connected.

7.1.9 Port J

Port J is multiplexed with 8 chip-select signals identified below.
MOTOROLA MC68328 DRAGONBALL PROCESSOR USER'S MANUAL
Note
Table 7-4. Port J Bit Functions
Bit Port Function Other Function
0 Bit 0
1 Bit 1
2 Bit 2
3 Bit 3
4 Bit 4
5 Bit 5
6 Bit 6
7 Bit 7
CSC0
CSC1
CSC2
CSC3
CSD0
CSD1
CSD2
CSD3
Parallel Ports
7-11