MC68331CEH16 Datasheet, PDF (30/84 Pages) Freescale Semiconductor, Inc – 32-Bit Modular Microcontroller

Freescale Semiconductor, Inc.
3.5.2 Pin Assignment Registers
The pin assignment registers (CSPAR0 and CSPAR1) contain pairs of bits that determine the function
of chip-select pins. The pin assignment encodings used in these registers are shown below.
Table 12 Pin Assignment Encodings
Bit Field
00
01
10
11
Description
Discrete Output
Alternate Function
Chip Select (8-Bit Port)
Chip Select (16-Bit Port)
CSPAR0 —Chip Select Pin Assignment Register 0
$YFFA44
15
0
RESET:
0
14
13
12
11
10
0
CSPA0[6]
CSPA0[5]
9
8
CSPA0[4]
0 DATA2 1 DATA2 1 DATA2 1
7
6
CSPA0[3]
DATA1 1
5
4
CSPA0[2]
DATA1 1
3
2
CSPA0[1]
DATA1 1
1
0
CSBOOT
1 DATA0
CSPAR0 contains seven 2-bit fields that determine the functions of corresponding chip-select pins.
CSPAR0[15:14] are not used. These bits always read zero; writes have no effect. CSPAR0 bit 1 always
reads one; writes to CSPAR0 bit 1 have no effect.
CSPAR0 Field
CSPA0[6]
CSPA0[5]
CSPA0[4]
CSPA0[3]
CSPA0[2]
CSPA0[1]
CSBOOT
Table 13 CSPAR0 Pin Assignments
Chip Select Signal
CS5
CS4
CS3
CS2
CS1
CS0
CSBOOT
Alternate Signal
FC2
FC1
FC0
BGACK
BG
BR
—
Discrete Output
PC2
PC1
PC0
—
—
—
—
CSPAR1 —Chip Select Pin Assignment Register 1
$YFFA46
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
0
0
0
0
0
0
CSPA1[4]
CSPA1[3]
CSPA1[2]
CSPA1[1]
CSPA1[0]
RESET:
0
0
0
0
0
0 DATA7 1 DATA 1 DATA 1 DATA 1 DATA 1
[7:6]
[7:5]
[7:4]
[7:3]
CSPAR1 contains five 2-bit fields that determine the functions of corresponding chip-select pins.
CSPAR1[15:10] are not used. These bits always read zero; writes have no effect.
CSPAR0 Field
CSPA1[4]
CSPA1[3]
CSPA1[2]
CSPA1[1]
CSPA1[0]
Table 14 CSPAR1 Pin Assignments
Chip Select Signal
CS10
CS9
CS8
CS7
CS6
Alternate Signal
ADDR23
ADDR22
ADDR21
ADDR20
ADDR19
Discrete Output
ECLK
PC6
PC5
PC4
PC3
30
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